CA1305577C - Optical article containing a polymeric matrix exhibiting a high level of second order polarization susceptibility - Google Patents

Abstract

AN OPTICAL ARTICLE CONTAINING
A POLYMERIC MATRIX EXHIBITING A HIGH LEVEL
OF SECOND ORDER POLARIZATION SUSCEPTIBILITY

Abstract of the Disclosure An optical article is disclosed containing, for the transmission of electromagnetic radiation, a medium exhibiting a second order polarization susceptibility greater than 10-9 electrostatic units comprised of organic polar aligned noncentrosymmetric molecular dipoles. The molecular dipoles form repeating units in a cross-linked polymeric matrix.

Description

AN OPTICAL ARTICL~ CONTAINING
A POLYMER I C MATR I X EXH I B I T I NG A H I GH LEVEL

Field of the Invent~on The invention rel~tes to optical ~rticles, p~rticul.~rly articles which exhibit effect~
attributRble to the pol~rizstiGn of electromagnetic radiation. The invention relates specifically to optical ~rt~.cle~ which exhibit effect~ attribut~ble to 10 the nonline~r pol~rization of electromagnetic radiRtion .
of the Invention : The signiflcant pol~rization components of ~
medium produced by cont~ct with an electric field Rre 15 first order polarization (line~r pol~rization), second order polarization (fir~t nonline~r polerization), and third order polarization (second nonlinear pol~rizstion). On a molecular level this c~n be expre~sed by Equ~tion l:
20 (l) P = aE + ~E2 ~ yE3...
where ~ P is the tot~l induced pol~riz~tion, -~ E is the local eIectric field created by ~; 25 electrom~gnetic r~diation, and a, B, snd y ~re the fir~t7 ~econd, and third order pol~riz~bilities, each of which i9 ~ function of molecular properties.
~ B ~nd y are ~190 referred to ~ first and ~econd ; 30 hyperpolarizabilitie~, respectively. The molecular : level terms of EquQtion l ~re first order or line~r polariz~tion aE, ~econd order or f~rst nonlineQr ~` pol~rization ~E2, ~nd third order or second : nonline~r polarization yE ~
: 35 On a m~cromoleculQr level corresponding relation~hip~ can be expre~sed by Equation 2:

: .
.
.

(2) ~ = X~l)E ~ ~(2)E2 ~ ~3)E3 where P is the total induced pol~riz~tion, E 1~ the local electric field created by electrorn~gnetic radiation~ ~nd x(~ 2), and x(3) are the first, second~ and third order pol~rization susceptibil~ties of the electroma~netic w~ve tr~n3mission me~ium.
~ x(2) ~nd x(3) ~re ~l~o referred to RS the fir3t ~nd ~econd nonlinear polarization su~cepti-bilities, respectively, of the tran~mis~ion medium.
The macromolecul~r level term~ o$ Equation 2 ~re flrst order or lineHr polarization ~E, ~econd order or 15 first nonlinear polarization x(2)E2, and third order or second nonlinear pol~rization x(3)E3.
Second order polar~zation (~(2)E2~ has been suggested to be uqeful for 8 variety of purposes, including optical rectific~tion (convertin~
~: ~ electrom~gnetic radiation input into A DC output), ~enerating ~n electro-optical (Pockels) effect (us~n8 combined electrom~gnetic radiation Rnd DC inputs to alter during their application the refr~ctive index of the medium), ph~se ~lter~tion of elPctromagnetic ~: 25 radiation, ~nd parametric ePfects, most notably frequency doubling, ~190 referred to ~g second harmonic generation (SHG).
To achieve on ~ m~cromolecul~r level ~econd order pol~rization (x~)E~) of any significant ~ magnitude, it i3 es~enti~l th~t the tr~nsmission : : medium exhibit ~econd vrder (fir~t nonllnear) polarization su3eeptibilities, ~(2?, ~reater than _g electro~tAtic unit~ (e~u~. To re~ e such v~lue~ of x(2~ ~t i~ necessary th~t the fir~t 35 hyperpolarizabillty ~ be ~re~ter than 10 30 esu.
For ~ molecule to exhi~it v~lue3 of 8 greater than zero, it i5 neces~Rry th~t the~mol2cule be aqymmetrical about it~ center--that i~, noncentro-~ymmetric. Further, the molecule must be capable of o~cillating (i.e., re~onating) between an excited state and a ground state ~iffering in polarity. It 5 has been observcd experimentally ~nd explsined by theory th~t large ~ values sre the re~ult of large differences between 8round and excited state dipole moments a~ well ~s lar~e oscillator strengths ~i.e., large charge trsnsfer resonance efficiencie~).
For ~(2) to exhibit a usefully largP
value it is not only nece~sary ~hat ~ be large, but, in addition? the molecul~r dipoles must be Qli~ned so a~ to lack inver~ion ~ymmetry. The lQr~sst values of x(2) are realized when the molecular dipoles ~rP
15 arran~ed in polar alignment- e.g., the ~lignment obtalned when moleculsr dipoles are allowed to align themqelves in ~n electric field.
D. J. Williams, "Organic Polymeric and Non-Polymeric Materials with Large Optic~l 20 Nonllnearltie~", An~ew. Chem. Int. Ed. Engl. 23 (1984) 690-703, postulates mAthematically and experimentally corroborates Hchievement of ~econd order polarization su~ceptibilit~e~ x(2) using org~nic molecular dipoles equallin~ ~nd exceedin~ those of conventlonal 25 inorganic noncentro~ymmetric dipole crystal3, such a lithium niobate and potassium dihydrogen phosphate.
To obtain the polar alignment of the org~nic molecul~r dipoles necessary to large values of x~2) Williams dispersed sm~ll amounts of the or~anic molecular 30 dipoles a5 ~ue~t molecule3 in host liquid crystalline polymers. Upon heatin8 the host polymer~ ~bove their gla~s tr~nsition temperature~, poling in Rn externally ~pplied electrlc field to produce the desired polAr ~lignment of the molecular dipoles, ~nd then cooling 35 with the field applied, orgRnic films with the measured levels of x(2) were obtalned.
:

' In addition William3 notes the f~bricstion of films with large v~lue3 of ~(2) u~ing Lsn~muir-Blodgett ~LB) film construction technique~, ~uch polydi~cetylene ch~in~ formed by LB technique~.
5 Willi~ms further ~u~ge3ts the r~diation p~tterning of the~.e fllm~.
Zys3 ~Nonlinear OrgRnic Materlals for Integrated Optic~", Journ~l of Molecul~r Electronics, Vol. 1I pp. 25-45, 1985, though ~ener~lly cumulative 10 wlth Williams, provide~ ~ review of passlve linear li~ht ~uide con~truction technique~ and el~borates on LB film construction techniques including radiation p~tterning, showing in Figure 8 an LB film construction converted into a linear polymer.
Garito U.S. Patent 4,431,263 discloses nonline~r optical, piezoelectric, pyroelectric, waveguide, and other articles containing a linear polymer of a diHcetylene.
Choe U.S. P~tent 4,605,869 discloses ~ laser ~ frequency converter containing a linear polymer of the structure:
1) y !

2 5 T îî
t --(Y =
~ \., l!
T
N ~
CH3 ~H3 where n is sn integer of at le~st 3 and Y 1~ disclosed to be "nitro, cyano, tri~luoromethyl, ~cyl, carboxy, ~lkanoyloxy, aroyloxy, car~oxymido, ~lkoxy~ulfonyl, ~ryloxy~ulfonyl, and the like.'l ~3~557~

Singer, Sohn, ~nd Lal~ma, "Second Hermonic Generation in Poled Polymer Films", ~ . Phys. Lett., Vol. 49, No~ 5, 814/86, pp. 248-~50, di~closes placin~
the ~zo dye Disperse Re~ in poly~methyl meth~cryl~te), 5 spin coatlng on ~ transparent electrode of indium tin oxide, overcoating with 8 th~n lay~er of gold, reisin~
the film above its glas~ transitic)n temper~ture, applying a polln~ electric field, ~nd then the film well below its gla~s tr~nsition te!mperature with the 10 ~ield applied~
~ hoe et al U.S. Patent 4,659,177 discloses organic nonllnear optlcal medl~ containing ~n organic molecular dipole. Both LB film assembly techniques and dispers~l of the org~nic moleeul~r dlpole as a 15 ~uest in a line~r polymer host followed by heating above the gl8sS tr~nsition temperature, poling in an electric field, and cooling with the field applied, &re disclosed.
Sagiv U.S. P~tent 4,539,061 discloses ~
20 process for the formation of "~elf-~sembled" ~ilms on substrstes, where the term "self-aasembled" is employed to indicate the film can be formed from succes~ive monomolecular layers th~t are e~ch ` ~pont~neously oriented on deposition. A first -; 25 monolayer i9 formed by reacting with or ~dsorbing on the curf~ce of a subqtr~te a compound consisting oÇ a hydroc~rbon linking moiety ~oining ~ bonding group and e bonding group precursor. After the layer is deposited the bonding gorup precur~or can be converted 30 to a bonding group and the deposition procedure repeated.
Summary of the Invention It has been reco~nized that optical artlcles contalning9 for the transmission of electromagnetic 35 radi~tlon, ~ medium which exhibitQ ~ hi~h second order pol~r~zation susceptibility provided by organlc molecular dipoles offers the potenti~l for performance , .
., .
.

advantageq over corre3pond1ng optieal art~cle3 employing conventional inorg~nic molecular dipoles, b~sed on ~uperior fir~t hyperpolariæabilltle~ B, hi~her tr~n~parencies, ~nd ~re~ter ~dapt2bility oÇ the 5 organle molecul~r dipole~. To realize thls potential fully, however, it i~ nece~s~ry to provide a tr~nsmi~ion medium in which organic molecular dipole~
are ~rr~nged in stable polar alignment ~nd exhibit ~
hlgh hyperpolhriz~b~lity den~lty (B/V~ where V ~ thP
10 volume of madium).
The highest hyp~rpolarizability d2nsltie3 of polar ~ ned org~nic molecul~r dipole have been achieved in Langmuir-Blod~ett film con~tructi4ns.
Unfortun~tely, the~e are inherently dis~dv~ntageou~, 15 ~ince they mu~t be a3sembled by depositing ~ucces~ive monomolecular l~yers, making construction of ~11 but thin layer transmission media time consuming ~nd inconvenient. Addition~lly, LB Eilm~ a~ desposited are readily d~mag~d. This is p~rticul~rly true of 20 ~ult~layer a~semblies, which ~re often unstable.
~ Although polymerization of LB films ~fter assembly has ;~ been propo~ed, only reaction of the org~nic molecular : dipole~ within ~ sin~le LB layer to form linear polymer~ hR~ been suggested.
The monomolecular depo~ition of LB fllm assemblies can be avoi~ed by polin~ organic molecul~r :~ dipole~ through the applic~tion of an externally applied DG field. Unfortunately, poling techniques heretofore taught by the srt have resulted in 30 ~ignific~nt reductions in the hyperpolari~ability den~ity B/V of the tran~mission medium.
When organic molecul~r dipoles ~re dispersed in llnear polymers, such as liquid crystals, the solubility of the molecular ~ipole is limited. R~rely 35 ean concentr~tions of the orgsnic molecul~r dipole approaching 20 percent by weight ~e reQlized. He~tin~
of line~r polymer~ ~bove their glass tr~nsition ~3~

temper~tures to allow polar ~lignment of the molecul~r dipoles inherently incre~3e~ random kinetic motion tendin~ to offset poling. Ph~e ssp~ration ~nd therm~l degr~d~tion of the he~ted m~teri~ls ~re also 5 m~tters of ~ignificant concern.
Finally, it iY noted th~t to the extent polymeric ~trice~ have been employed to hold organic molecul~r dipoles in pol~r alignment, the polym~rs h~ve been line~r polymers. While llne~r polymers c~n lo be ~olld in ~ppear~nce, they ~re in reality vi~cou~
liquids. If the tr~n~mis~ion medium is inadvertently reheated to or ne~r the gl~ temperature of thle linear polymer ~fter poling, the polar alignment of the molecul~r dipoles i~ lo~t. Further, the molecul~r 15 dipole~ ret~in some freedom for rearrangement in line~r polymer matrlces even st lower temper~tures.
This iq A matter of signific~nt concern, since in many applic~tion~ optic~l articles become intern~lly he~ted by energy dissipation during the tr~nsmission of 20 electromagnetic rsdi~tion.
In one ~pect thi~ inYention i3 directed to ~n optical srticls containing, for the tr~nsmission of ~: electrom~gnetic r~di~tion, a medium exhib{ting a ~ ~econd order polariz~tion ~usceptibility 8re~ter than :~ 25 10 ~ electro~t~tic unit~ compriqed of organic polar .: aligne~ noncentrosymmetric molecul~r dipoles having sn electron donor moiety linked through a conJug~ted bonding ~y.qtem to ~n electron ~ceeptor moiety to permit o~cill~tion of the molecul~r dipole between 8 30 ground state exhibitin~ ~ fir~t dipole moment ~nd ~n exclted st~te exhibiting a differin~ dipole moment.
The molecul~r dipole~ are chsr~cterized in th~t the moleeul~r dipole3 form repe~t~ng unit3 in A
cros~linked polymeric mstrix.
35 Brief De~criptlon of the Lr~Gi~
Figur~ a 3econd h~rmonic gener~tin8 optical ~rticle.
' . .

~3C~ 7~

--B~
Figure ~ is ~ DG signal providing optic~l ~rticle.
Figure 3 i~ an electrom~gnetlc beam di~placement optlc~l article.
Fi~ure 4 i~ ~n &ltern~tive form of ~ second harmonic gener~tin~ optic~l ~rtic,~l.
Fig-!re 5 i an optical ~rticle for ~chieving p~rametric effects.
Figure 6 i~ a ~ection t~ken ~long ~ection 10 line 6-6 in Figure 5.
Figure 7 iY ~n optic~l article for achieving pAr~metric effects an~ pha~e ~hifting~
De~cription of PreEerred Embodiments : The followin~ ~re illustr~tive of opticsl ~ 15 ~rt~cle~9 ~atisfying the invention exhibiting eiFfects ; ~ttributable to second order polarizationo Referring to Figure 1, the optical Qrticle 00 i5 c~pable of gener~ting a second hsrmonic o~
electrom~gnetic r~distion 101 ~upplied to it.
20 Incoming electromagnetic r~di~tion is introduced ~: through input me~n~ 103, shown as ~ first pri~m, into an optic~lly active tr~n~missiDn medium 105 which ~:~ exhibit~ ~ high level (~ 10 9 e~u) 3econd order or fir~t nonlinear polariz~tion susceptibility9 25 herein~fter referred to ~imply as the opticelly active ::~ tr~nsmi~on medium ~ccording to the invention or, ~ more ~uccinctly, as the optically active transmission : medlum. Electromagnetic r~di~tion i5 tr~nsmitted throu~h the medium 105 to output me~n~ 107, ~hown 8~ a : 30 ~econd pri~m. In the ~imple~t form of the optic~l ~rtlcle neither the input nor output prisms sre required. E~c~pe of electromRgnetic r~di~tion from the tran~mission medium can be minimized by loc~ting optlon~l guiding element~ lO~ ~nd 111 ~bove ~nd below 35 the tr~nsmis~ion medium. The guiding elements c~n m~nimize r~di~tion 105~ by being cho3en to exhibit lower refractive index th~n the trsn~mi3310n medium.

-` ~3~S~
_g_ AdditionRlly or alternatively, the guiding elements can be choqen to be reflective to the electromagnetic r~diation.
When the transmiqslon medium i~ constructed 5 ~ccordi~l~ to the requirement~ of the invention, ~pecifically described below, at lea~t ~ port~on of the electrom~gnetic radiation enterin~ the tr~n~mlssion medium will be alterred in frequency durin~ it~ tr~vel throu~h the medlum. More 10 spQcifically, ~ ~econd h~rmonic of the frequency will be gener~ted. The electromagnetic r~diation leaving the output me~ns, lndic~ted by ~rrow 113, exh~bit~
both the origin~l frequency o~ the lnput radi~tion and a 3econd h~rmonlc of this frequency. The electro-15 ma~netic radiation retaining the original frequencycan, if desired, be removed by pas~ing the electromagnetic radiQtion le~ving the Rrticle through a filter 115 capable of ebsorbing radiation of the origin~l frequency while tr~nsmittin~ higher fre~uency 20 (~horter w~velength~ portion~ of the electromagnetic rRdiation. By employing one or ~ combination of filters any bro~d vr n~rrow frequency ~and of - el ctrom~gnetic radiation can be rst~ined in the tr~n~mitted output electrom~gnetic r~di~tion 117.
Referring to Figure 2, Qn optic~l ~rticle 200 is shown capsble of producing ~ DC potential when : electrom~gnetic radiation 201 is supplied through input me~ns 2~3, ~hown a5 a prism, to optically sctive tr~n~mi~sion medium 205, which can be identical to 30 medium 105, de~cribed a~Qve. When electromagnetic radiation is being tran3mitted through the medium potenti~l d~ference ig produced between upper electrode 207 and lower electrode 209 in electrical cont~ct with the upper ~nd lower surfaces of the 3S tr~nsmi~sion medium. Electrical conductor~ 211 and 213 can be used to relay the potenti~l o$ the upper ~nd lower electrode~ to ~n electronic response unlt f'~r 215. The electron~c rPsponse unit cen in its s~mplest form be a unit that provides ~ digltal respon3e indicatlve of the the pre~ence or absence o~
electr~magnetic radiation in the transmission medium.
5 A~tern~tively, the electronlc respon3e unit can provide ~n analo~ response indicstive not only of the presence, but also the inten~ity s)r wavelength of electr~magnetic r~dlation in the tran~mi~sion medium.
Referring to Figure 3, the optical ~rticle ~ 300 is cspable of physic~lly di~plQcing a beam 301 of electrom~netic rQdiation being transmitted through it as a function of th& concurrent receipt of a DC bias.
Optically active transmi~sion medium 305, which csn be identic~l to optic~lly active medium 105 or 205, is 15 pro~ided with trQnsparPnt upper ~nd lower electrodes 307 end 309. The electrodes can, for example, be th$n layers of a vacuum vapor deposited metal or metal oxide -e.g., indium tin oxide. An electrom~gnetic :rAdiation input me~ns, shown as prism 311, :l~ located ~:20 on the upper tran~parent electrode. The electro -~;magnetic radiation p~sses through the prism ~3 indic~ted by arrow 313. When the s3lectrom~gnetic radiation ~nters the transmission medium, it follow~
~ither path 315~ or path 315b. Depending upon which 25 of the two alternative p~ths are followed, the ~irst electromagnetic r~dietion either travels ~long path 31 7a or 31 7b upon emereing from the lower transparent electrode. The p~ths 315a and 317a together constitute ~n A p~th throu~Bh the optical ~rtlcle while 30 the paths 315b ~nd 317b together con~t~tute a B pE~th through the opt$cal &rt~cle. Sensing units 319a ~nd 319b Rre located to receive electrom~gnetic radiation traveling along the A ~nd B paths, respectiYely. It is ~pp~rent th~t only one of the two ~en~in8 unit~ is 35 e3~enti~1, since f~ilure to sense electrom~gnetic r~diation can be employed to indic~te that the electrom~gnetic ra~iation has shifted to the alternRte ~3q;~S~ii77 p~th.
Shlfting of Qlectrom~gnetic radi~tion between the A ~nd B path~ chieved by supplying a DC bins to the upper And lower electrodes whlle ~r~n~mi~sion 5 of the electromagnetic r~di~tion through the optic~lly ~ctive tran~mis3ion medium i~ occurrlng. To accompli~h the requlred DC biB~ ~ DC potenti~l source is ~hown connected to the upper ~nd lower electrode~
by electrical conductor~ 327 ~nd 329.
Applic~tion of the DC bias ~lters the refractive ind~x o$ the tr~nsmi~sion medium when it i~
formed of 8 m~teri~l exhibiting ~ ~igni~ic~nt ~econd order ~u~ceptibility. This c~u~es the ~ir~t electrom~gnetic radiation beam to be refracted ~t 15 different ~n~le when the tran3mi3sion medium i~
electric~lly bissed, and this chan~e~ the first electromA~netic r~diAtion path through the tr~nsmi~ion medium. In some in~tances the refractive index of the tranqmi~ion medium is increased by the 20 electric~l bia~ ~nd in other $n5tance9 lowered by the electric~l bia~, depending upon whether the moleculAr dipole contained within the tr~n3mis3ion medium exhibits ~:po~it$ve or negative first hyperpol~riz bil~ty B.
In Figure 4 ~n optical ~rticle 400 1~ shown comprl~ed o~ A reflective ~ubstr~te 401 ~nd an ; Sptically active tran~mi~ion medium 403 according to ; the invention shown in the form of a l~yer.
Electromagnetic radi~tion i~ supplied from a ~ource 30 405 ~ indic~ted by ~rrow 407. The electromagnetic ~: r~di~tion trav2r~e~ the optic~lly active tran~mi~ion ~ medium, is reflected by the substrate, and tr~ver~es :~ the optically a~t$ve tr~nsmi~sion medium ~ ~econd time. ElectromQgnetic rAdiation le~ving the optic~lly 35 active transmi~sion medium i~ indic~ted by ~rrow 409.
' : A sen~or ~11 which is re~pon~ive to the ~econd harmonic of the input electrom~gnetic r~diation, but :

itJ''~

not radi~tion ~t the wavelength of the input r~diation, i~ shown provided to r~ceive electro-m~Bneti~ r~di~tion from the l~yer 403. Inste~d of employing a sen~or th~t is select$vely respon~ve to 5 the ~econd hRrmonic w~velength, a ~ensor with ~
bro~der frequency b~nd of re~ponse c~n be employed in combin~tion with one or more filter elements, ~
de~cribed ~bove in connectlon with Fi~ure 1. The thinner the lQyer of the opt~cally ~ctive tr~nsmission 10 medium, the hi~her the intensity of the input electrom~gneti~ r~di~tion must be in order to ~chleve ~ iven output of second harmonic rediation. In the limiting ca~e the optic~lly ~ctive tran3m1~ion medium c~n be ~ monomolecular oriented molecul~r dipole layer.
In Figures 5 and 6 ~n optic~l ~rticle 500 ~ccording to the invention i5 shown capsble of inducing pRrametric effects, such ~s second h~rmonic gener~tion, by acting on input electrom~gnetic radi~tion, indicated by arrow 501. To ~chievP
20 slter~tion of the input radiation R tr~n~parent optic~l w~ve~uide 503 of any conventional type is provided h~ving on its external surf~ce ~ l~yer of ~n optic~lly ~ctive tr~nsmission medium 505 according to the lnvention, which can h~ve the s~me properties 25 the medium 105, de~cribed above. The optic~l w~veguid~ 503 is normally optic~lly pas~-lve- that is, : exhi~it~ no ~igni~icant levels of nonlinear (~econd or thlrd order) polarization.
Me~n~ 507, 3hown QS ~ pri~m, i~ provided to 30 introduce the input electrom~gnetic radiation into the w~ve~uide. Mesn~ 509~ shown ~s ~ pri~m; i~ provided to retrieve electrom~gnetic r~di~iton from the ; w~veguide. Althou~h the optichlly Qctive tr~nsmission medium is shown interpoqed between the input ~nd 35 output pri~m~, i is ~ppreci~ted tha~ sn interposed l~yer i~ not requlred in these loc~tions.

S~

As the input electromagnetic r~diation traverses the waYeguide, a portion of the r~diation will impinge on the surrounding liRyer of the optically active trsnsmi3sion medium and be refrQcted back into 5 the wave~uide. To ~void e~c~pe of electromagnetic radi~tion ~ reflective layer, not shown, can be coated over the optically active tr~nsmi~sion medium.
Succe~ive impingements of tr~nsmltted r~di~tion on the optically ~ctive medium result ln meesure~ble 10 p~r~metric effects, such as second harmonic generation.
In Figure 7 ~n opticRl article 600 is shown c~pable of producing u~eful perametric effects simil~rly as optical article 5~0, but exhibiting gre~ter capebility ~or better phase matching, such 15 th~t desired for improved efficiency ~econd harmonic generat~on. A substr~te 601 is shown ~uppDrting 3uperimposed w~ve~uide layers 603, 605, 607, ~nd 609.
Whlle four superimpo~qed layers ~re shown, in practice ~ny odd or even number of superimposed lsyers can be ~ 20 provided. The odd l~yers (603 an~ 607) in the .; sequence can be formed of ~n optically active tr~nsmi~sion medium according to the invention (simil~rly a9 medium lOS) while the even layers (605 ~nd 609) can be formed of ~ passive or line~r optical 25 medtum, a~ described ~bo~e. Altern~tively, the optically active and passive transmisqion ~edia layers can be reversed in order.
To ~chieve useful parametric effects, electromagnetic r~diation, indic~ted by ~rrow 611 is 30 ~upplied to the w~veguiding l~yers through input me~ns 613, ~hown es 8 priqm. In p~slng through the ~ w~veguiding layers to output mean~ 615, 3hown a~ ~
~ pri~m, the optically active ~nd p~ive media l~yer5 : together ~lter the form of ~he electromagnetic 35 radiation, indicated by output errow 617, ~o thst :- p~r~metric ~e.g., ~ecsnd h~rmonic) effects &re more c~ficiently gener~ted.

Th~ optic~l ~rticle constructions described above sre exemplary of a l~rge variety of po3sible differing optical article constructions. The present invention is compatible with ~ny convention~l 5 con~truction of en optic~l article relying on ~
siKnificQnt second order polarization ~usceptibility to produce ~ useful effect. For ex~mple, wheres~ in connection with Figure 5 an optic~l ~rticle is di~clo~ed in which the optically Qctive tr~nsmis~ion lo medium ~urrounds ~ ~ub~trste, which c~n hQve linear optic&l properties, Zy~s, cited above, in Figure 2~d) disclose~ ~ust the conver~e ~rr~ngement9 in which the optic811y ~ctive tr~nsmi~ion medium forms ~ core el~d with ~ shell of ~ linear optlc~l tr~n~mission medium.
l5 Zyss 81~0 di~closes an ~rr~ngement in which the optically acti~e tr~nsmission medium i~ located ~n ~
groovc on the surf~ce of a line~r optic~l trAnsmission substr~te. All of the optic~l article constructions of Zy~ exhibiting second order nonpoI~riz~iton 20 e~fects c&n ~e ~pplied to the practice of this invention.
An es3enti~1 component of e~ch of the opt1cQl articles of thi~ invention is ~n optic~lly ~ctive tr~n~mission medium exhibit~ng a ~econd order 25 pol~rization ~usceptibility gre~ter th~n 10 9 (prefer~bly gre~ter th~n lO 8) electrostatic unit~
cont~ining pol~r ~ligned molecul~r dipoles crosslinked to form fl polymeric m~trix. The molecul~r dipole~ ~re comprised of Hn electron ~cceptor moiety bonded to ~n 30 electron donor moIety by ~ linking moiety providing con~ug~ted ~ bondln~ system to permit oscillAtion of the molecul~r dipole between ~ ground stste exhibitin8 first dipole moment ~nd ~n excited state exhibiting ~ differing dipole moment. The molecul~r dtpole~ are 35 repre~ented 1n formuls peir~ by the o~cill~tion ~re~onance) ground state ~nd excited state extremes, since the3e lend them~elve~ to repre~entation by :~L3~5S77 --15~
chemicRl formul~e. Formula pa1r~ are useful in br~cketing the ranKe of structur~l v~riance, even thsugh it i~ recognized th~t ln pr~ct1ce neither of the o~c.lll~tion extreme~ m~y be sctu~lly fully 5 re~lize~. The molecul~r dipol~s of this invention are general.Ly represented by Formula E'~lr 3.
(33 ¦ E ~ LQ
" _ r) _ - Ae -ll _ D _--LQ
where A i~ sn electron ~cceptor moiety;
D i~- Qn electron donor moiety;
: E is ~ linking moiety, ~peciflcally a con~ug~ted bonding ~ystem, which provide~ a pQthw~y for chRrgs tr&nafer re~onance;
n integer of ~rom 1 to ~; and L i~ a cro~qlinking moiety.
For convenience the molecular dipoles are n~med usin~ their ground ~tate structures, unles otherwi~e noted.
The electron acceptor moiety A can take any 30 convenient conventional ~orm. For example, the electron ~cceptor moiety can be an oxo, cy~no, sr nitro moiety, as di~clo~ed by Will~am~, cited above.
:~ In ~ ~peciEic~lly preferred $orm sf the invention the ~ : electron acceptor moiety A is a Rulfonyl moiety.
:~ 3S Optical ~rticle~ contalning ~ polar aligned organic : molecul~r dipole containing a 3ul~0nyl moiety a~ an electron ~cceptor. When the electron acceptor moiety ~3~?557'7 i3 ~ sulfonyl moiety~ it can be represented by Formul~
P~ir 4:
(4) R

O=S=O
I

I
O- S~
where : Rl i~ An option~lly substituted hydroc~rbon 15 moiety, with one of the ~ubstituents optionally being ~ crosslinking moiety L.
: The Plectron donor moieties can take ~ny convenient convention~l form. The electron donor moiety c~n be ~n ~mino moiety. Prim~ry, secondary, 20 ~nd tertiary amino moieties ~re contempl~ted for use, with the latter bein~ most preferred and the former being le~st preferred. Only the second~ry and terti~ry ~mino moieties allow for 3ubstituent ~: modification nf propertie~ through option~
: : ~5 substitution of a hydrocarbon moiety simil~rly ~s the sulfonyl moiety, ~nd only the tertlary amino moiety produces the most hi$hly pol~r excited st~te. When the eleetron donor mniety, it c~n be represented by Formul~ Pair 5.
30 (5) .~ ~

2 Il+ 3 R--N - R
where . : i .

~L3(~5~77 R~ and R3 are independently L, hydrogen, or option~lly substituted hydrocarbon moieties.
In~tesd of employing an amino group ~s an electron donor moiety, it is spec'Lfic~lly oontemplated 5 to employ an oxy or thio electron donor moiety. When such oxy ~nd thio electron donor r~oietles can ~e represented by Fcrmul~ P~ir 6.
(6) I

X

X+
l4 where R4 is an optionally 3ubst~tuted hydroc~rbon : moiety, with one of the substituents optionally being one of the cros~linXin~ moieties L and ; X is oxygen or sulfur.
The moiety E linXing the electron ~cccptor and donor moietie~ is ~elected to ~atisfy three fund~ental chsr~cter~stics. First, it i5 cho~en so that the molecule will be noncentrosymmetrlc, thereby exhibiting ~ dlpole moment even in lts ground state.
Second, lt is chosen to provide suffic~ent sp~tial ~ep~rati~n of the electron donor and acceptor moieties to provide a l~r~e dipole moment in the polar exc1ted state of the electron donor ~nd ~cceptor moieties.
Third~ the linking molety i^Q chosen to permit efficient o~clllation or charge ~ransfer re~on~nce between the ground ~nd excited ~tates. Thls result3 In l~rge diffe~ences between the excited ~t~te ~nd 8round state dipole moments.
A con~ug~ted ~ bonding system can sati~fy ~ll three requ~rement~. On lt~ most elemental level ~uch A bonding ~ystem c&n be provided by chain~ of methine ~ ~ . k . H ., methenyl and methylidyne) ~roups, which are (except ~ ~pecific~lly noted) to be understood ~s including ~ubstituted forms. Such 5 ch~ln~ c~n optionally include one or mor~ ~za (-N=) moietie~.
To s~ti~fy the requirement f~r n~cillation or ch~rge tran~fer reson~nce, it i.~ e~ential that the resonance path be defined by an even number of ~tom~.
10 The number of ~toms 1n the re~onRnce path between the electron donor and ~rceptor is preferably at le~t 4 ~nd optimally at leR t 8~
While increa3ing the number of ~toms in the re~onance path ~hould increase the excited st~te 15 dipole moment, it al90 tends toward nonplanar molecular conform~tion~ which le~d to lo~e~ in hyperp~l~rlzabllity ~en~ity, defined Rbove, a~ well a9 thermal ~nd other energy loaYe~ (e.g~, 1053e~ in tran~parency), 50 th~t ~t fir~t diminishing gain~ ~nd 20 then overall lo~e~ reault from incre~sing the number ~: of ~tom~ in the re~onance path. It i~ generally preferred that the number of ~tom~ in the resonance p~th between the electron donor ~nd acceptor be 20 or la~s and optimally 14 or le~s.
In ~ preferred form the linking moieties can be represented by Formul~ P~ir 7.
(7) I G
1l m t ~ ~ 35 :~ G
G

m ~3~

where G ~9 independently in e~ch occurrence meth~ne or ~Z~ ~nd m i~ 4 to 20, preferably B to 14.
For 3ynthetic convenience it i3 generally preferred th~t no more th~n two ad~cent G ~roups be ~za ~roup Thus, both indlvidu~l ~z~ (-N=) ~nd dia~o (-N=N-3 8rouPS are contempl~ted to be present in the linkln~ moiety.
While the az~ groups permit no ~ubqtitution, the methine groupq can be sub~tituted, if desired.
Preferred linking moietie~ are those which have been ~t le~t parti~lly rigidized by substituents bridgin8 methine groups i~ the re~onance path. Rigidlzation of l5 the linking moiety reduce~ energy dl~ipatlon. In a specific~lly preferred form of bridgin8 subqtitution of the methine groups in the resonAnce path, the linking moiety i~ wholly or, prefer~bly, partislly arom~tized. Both c~rbocyclic ~nd heterocyclic 20 arom~tiz~tion i~ specific~lly contemplated.
:~ In ~ ~pecific preferred form of the invention the electron acceptor moiety A and the ~d~cent : termin~l portion of the linking moiety E c~n be repre~Pnted by Formula P~ir 8.
25 (8) : A

a ~ T

~ A ~

3 S Ra=i~ R

: where - ~IL3C~

A i~ an electron acceptor moiety and R~ repre ent hydro~en, ~ubstituent~ whlch to~ether ~ith the electron ~cceptor moiety collectively enhance the electron ~cceptQnce oÇ the 5 phenyl rin~ to whlch they ~re attached, option~lly inelu~ing sub~tituent~, such ~s hy~rocarbon ~ub~tituents, which ~re in turn 3ub~t~tuted with a cro~linking moiety L~ or ~ combin&tion thereof.
When the 2 lectron aeceptor moiety i~ ~
10 ~ulfonyl moiety SO~Rl ~nd the sd~cent atom of the linking moiety is an aza ~-N-~ group, the ~ulfonyl and ~ groupQ in combin~tion form a ~ulfon~mino group =N-S02Rl~ In ~ pecifle preferred form of the $nvention the terminel ~ulfonimino group ~nd an 15 ~d~cent aromQtized portion of the linklng group c~n be repre~ented by FormulR Pair 9.
(g) R
0=S=~

R~ il\ ~il=Ra r, t Rl , ~: O~S=O
~: 30 , ~!
Ra i~ =R~

; 35 where R~ and Rl are Q~ previou~ly define~.
In ~ ~pecific preferred form of ~he invention the electron donor moiety D ~nd the ad~acent termin~l ~SS~7 port~on of the linking moiety E cnn be represented by Formula P~ir 10.
(10) Rd_I~ iJ R~

; Rd=I~ il=Rd D
15where : D i~ ~n electron donor moiety ~nd Rd represent hydrogen, ~ubstituents which together with the electron donor D collectively enhance the electron donation of the phenyl ring to 20which they ~re ~ttached, option~lly including : sub3tituents; such aq hydroc~rbon substituents, whic~
are in turn substituted with ~ crosslinking moiety L, ~:~ or ~ combin~tion thereof.
Wh~n electron don~tion i~ from a nltrogen ~: 25~tom, ~ termln~l ~romatic ri8idizing ring sy~tem : formed by ~ 4-pyridinium ~nd 4-pyrido tautomer i3 posgible, AS illustrated by the preferred dlpol~r ~:: compound~ of Formul~ P~ir 11 ~:

: 35 ::

~3~5~

(11) Rd=Q/ ~.=Rd I

R~ d l2 where Rd and R2 are a~ previou~ly deflned.
In ~pecifically preferred form3 of the molecular dipoles the linking moiety i~ ~romatized ~d~cent both the electron ~cceptor moiety, acl indicated by Formulae 8 and 9, ~nd the electron donor : moiety, 89 lndicated by Formulae 10 ~nd 11.
A ~peclfically preferred cl~s~ of molecul~r dipole~ ~ati~fying the requirement~ of the invention are cro~linked 4~A-4'-D~tilbenes, where A ~nd D are : ~ previou~ly de$ined. In the~e stilbene~ the electron ~cceptor ~ulfonyl and electron donor moietie~
~: ~ Z5are each bonded to one terminal ~romatized portion o~
the conJugated ~ bonding linking moiety, with the ~rom~tized portion~ of the linkin~ moie~y being ~oined by an ethylene (vinylene) ~roup. When the ~ingle ethylene linking group of the ~tilbene is repl~ced by : 30two or more ethylene group~ within the re~onance path ch~in length limit~ nsted ~bove, highly advantageous ~nalogue~ are re~lizedO Sub~titution o~ individual methlne group~ with aza groups, particularly in the ethylenic porti~n of the link~e, ~re compatible wlth 3~chleving high B v~lue~. The ethylenical~y expanded and ~z~ 3ub~ituted ~tilbene vari~nt~ are hereinafter referred to ~g ~tilbenoid compound~, ~ince they ~re '~:

' , .
:., -, ' :~

~.3~S57~7 compound~ which share ~ignific&nt property ~imilaritie~ with ~tilbenes.
In ~ prefPrred form of the invention, the ~tilbene~ and ~tilbenoid compound~, eln be pre~ented by 5 Formul~ Psir 12:
(12) l o ~ ,6--R~
_ ~

G - LQ
I ¦ In R~ \,,=Rd _ Al3 ~: g Ra=q~ ~il=R~
~: 25 It I _ ~LQ
~ n Rd=l O=Rd where A, D, Q, L, R~, and p~d ~re a~ previou~ly 35defined;
D i~ ~n electron donor moiety;

-- :

G is independently in each occurrence ~ methine or ~z~ moiety, with the provi~o that no more than two ~za moieties ~re next ~d~acent; and n i~ ~n integer of from 1 to 3.
A ~ulfonimino group is incompatible with the qtilbenoid ~tructure~ of Formula ~P~ir 12~ One preferred clas~ of dipol~r compounda exhlbiting hi8h levels of hyperpolariz~bility incorpor~ting a termlnsl ~ulfonimlno ~roup ~re repre~ented by Formula Pair 13.

~; 20 '~
:

. ~ .

`' ~3055'~7 (:L3) N

R~ ~I li=R8 i1 ll LQ
Rd=~ d ~: 15 I ~ p _ _ ~1 ~ I e o=s=o :

~ ~li=RA ¦
~ ~ _ j (~ 'Q
3 0 : I

35 ;
wheFe ~' .

, ``` ~3~iJ,7~
-2~-D, Q, L9 Rl, R~, ~nd Rd ~re ~s previously defined;
G is independently in e~ch oocurrence a methine or aza moiety, with the proviso thAt no more th~n two az~
5moieties are next ~d~acent;
and p is 0 or 1.
In Formul~ P~ir 13 neithe~r of the two termin~l reson~nce path atoms of the l~nXing moiety lO~re included in ~ rigidizlng ~rom~ltic ring, but the rigidizing ~rom~tic rlng or rings are located next ~d~scent to each reson~nce path termin~l ~tom of the linking moiety. Note th~t either 6 or 12 atoms ~re pre~ent in the re~onance p~th provided by ~he linking l5moiety.
When electron don~tion is from ~ nitrogen Qtom, ~ terminal ~rom~tic rigidi2ing ring ~ystem formed by ~ 4--pyridinium And 4--pyrido tautomer is possible, ~s illustr~ted by the preferred dipolar 20compounds of Formula PQir 14.

~ 25 : 35 ;

.

~3~

~14) Rl O=S=O

R~ 11~ 11_R~

G --- I --LQ
:,; l~lq j Rdd=q o=Rd R~

~; 20 -- Rl 0-5=0 2 . ¦ R
: ` _ ¦
_ _LQ
G
3 0~ j R--3 5 whe L Rl R~2 R8, ~nd R are ~s pre-f iou~ly def ined;

.
''. ' : L3(;~S~i77 G i~ independently in e~ch occurrence a methine or ~z~ moiety, with the proviso that no more th~n two az~
moleties are next adJacent; ~nd q is an inte8er of from O to 3.
When the llnking moiety contAin~ two or more ~rom~ti.c ring3, it i~ ~pecifie~ll;y preferred th~t they be coplan~r, since coplan~rity ac.hieveq the highe~t hyperpolAri~&bility den~ities~ To pre erve the coplRn~rity of the rings it i~ prleferred th~t ~ny l0intermedi~te methine groups which ~re not p~rt o~ an ~rom~tic ring rem~in un~ub3tituted. However, sterically comp~ct methine ubstituent~ compatible with copol~n~rity, sueh a~ fluorine ~nd lower alXyl ~roups of from ~bout 1 to 3 carbon atoms, ~re 15contemplRted.
Where the electron donor and/or electron ~cceptor moietie~ ~re relied upon for crosslinking of the molecul~r dipole~, the ~rom~tic rlngs of the ~ linking moiety c~n be left unsubstituted while .~ 20~chieving high levels of perform~nce. In other inst~nce~ it m~y be synthetic~lly convenien~ to employ : the sromstic rings of the linking moiety as ites for cros~linkin~ the molecul~r dipoles. In either ~n~t~nce, it i~ appreciated thst the dipole moment : 25molecul~r dipole c~n be increased by employing ln ~vailable phenylene ring po~itions sub~tituents which supplement the electronic ~symmetry induced by the electron acceptor A moiety and the electron donor moiety D. Electron don~tin~ and ~ccepting properties 300f phenyl rings imp~rted by ~ubstitution have been extensively studied and qusntified by the ~sslgnment of H~mmett SigM~ value~. Sub3tituent~ which render phenyl rings electron ~cccpting sre a~igned po~itive H~mmett ~igm~ v~lue~ while negative Hsmmett sigm~
35value~ ~re ~ssi~ned to ~ub~tituent~ which render ~ phenyl rlngs electron don~ting. ~ydrogen ~tom~
- atta hed to phenyl rings sre ~ssi~ned a H~mMett ~igm~

- ~9 -value of zero. By algebraic~lly ~umming the H~mmett ~igma v~lue~ of substituent3 to a phenyl ring it i~
possible to ~rrive ~t a net Hammett si8m~ value for the phenyl r~.ng that is indic~tive of whether the 5 ubstil.uted phenyl rin~ is electron ~ecepting (lndicat~d by a po~itive net Hammett sigma v~lue~ or electron donatin~ (indic~ted by a neg~tive net Hammett sigmQ v~lue). Further, the algebr~lc ~um of the ~ubstituent HQmmett ~igma values quantifies the degree lOto which the ~ub~tituted ph~nyl ring is eleetron sccepting or donating.
Lange's Handbook of Chemi~try, 12 Ed., McGr&w-Hill, 1979, T~ble 3-12, pp. 3-135 to 3-138, li9t3 Hammett si8ma values for ~ lar~e number of 15commmonly encountered qub~tituent~. Ortho and para position ~ubstituentA u~u~lly exhibit identicaL
Hammett sigma valueq, which differ to only a llmited de~ree from met~ 3 igma valueA and c~n, in any event, be determined from published li~ts. Exem~lary simple ?OAub~tituent~ and their published meta Hammett ~lgma v~lues ~re primary and ~econd ~lkyl substltuent~, ~uch ~s methyl ~ = -0.07, ethyl a = -0.07, n-propyl O = - n. 05, i-propyl ~ = -0.07, n-butyl a = - O. 07, and ~ec-butyl a = -0.07. The~e alkyl 5substituent~ ~re ~ynthetieally convenient and therefcre contemplatefl. Alkyl substituents cont~ining tertiary carbon atoms and particularly tertiary ~lkyl groups tend to be even more hi~hly elPctron don~ting.
Aryl groups such as phenyl, a-naphthyl, and 30~-naph~hyl group~ are contemplated ~e.g., phenyl : a - 0.06). Other u~eful and specifically contempl~ted hydroc~rbon ~ubstituents include alkaryl ~ub~tituent~ (e.g., ~-methylphenyl), ~ralkyl ~ubstituent~ (e.g., benxyl a = -0.05 and phenethyl), 35alkenyl ~ub~tituent~ ~e.g. vinyl a = +0.02), ar~lkenyl ~ubstituent~ ~e.g. 9 2 phenylvinyl a = ~0.14~, ~lkynyl sub~tituent~ ~e.g., ethynyl ~3~ 7 o = ~0.21, prop~rgyl, ~nd ~-~utynyl~, ~nd ar~lkynyl substituent~ (e.~.> phenethynyl a = ~0.14).
Substituted hy~rocsrbon ~ubstituent~ ~re ~l~o contemplated, ~uch ~ h~loalkyl ~iub~tltuent~ (e.g., 5bromomethyl, chloromethyl a = -0..12, fluoromethyl, ~nd iodomethyl), h~losryl sub~tituent~ (e~
~-~romophenyl, m-bromophenyl, an~i ~-chlorophenyl, And hydroxy~lkyl sub~tituent~ (e.g., hydroxymethyl a = +O.OX).
It i~ specifically preferred to ~elect Ra sub~tituent3 independently from ~Imong known phenyl ring sub~tituents having a positive Hammett ~igma value ~nd to select Rd subqtituents independently from among known phenyl rin8 ~ub~tituent~ having 15negative Hammett si8ma value. However, it i5 recogni2ed that combinations of Ra ~ubstituents ~re possible, ~ome o~ which are electron donating, ~ome of which are es~entially neutral, and some of which sre electron accepting. Comblnations of Ra substituent3 20~re pos~ible which, to8ether with the electron acceptor moiety A, algebr~ically sum to a positive net H~mmett sigma value. Preferably the combination of RQ ~ub~tituents, without inclu~ion of the sulfonyl group, provide a po~itive net H~mmett ~i8m~ value.
; ; 25Similarly, ~ny combinat~QIl of Rd substituent~ i3 possible which~ to~ether with the elect~on donor, D, algebraieslly sum to ~ neg~tive net Hammett sigm~
value. Preferably the combination of R~
substituents, without lnclu~ion of the ~ubs~-ituent D9 30provlde ~ nega~ive net Hamme~t ~igma v~lue.
To svoid perturbation of the de~ired : re~onance pattern ~o one Ra ~ubstituent ~houl~ have a Ham~ett sigma v~lue more po~itive th~n that of the ::~ electron scceptor moiety, ~nd no one Rd ~ubstituent : .
35~houl~ have ~ Hammett sigm~ value more negRtive th~n th~t of the 01eotron donor moiety D. It i~ also important to be~r in mind th~t l~r~e B v~lues depend . ~
7'7 not only on achieving a large dipole moment, but also on achieving a lRr~e difference between the excited ~tate and ground ~tate dipole moments. Thus ~ub~tituents must be cho~en from amon~ tho~e which are 5compAtible with rever~ible ch~rge tran~fer -i.e., chsr~e transfer re~onance. Thus ~ub~tituents of the very hi.ghc~t ~nd lowest Hammett ~i~m~ values are preferably avoided.
It i~ recognized th~t two Md~cent R~ or l0Rd ~ub~tituents c~n, if ~e~ired, together form a ring fu3ed with the phenyl ring to which they are attached. Fused benzo rings Are Apecifiofllly contempl~ted. Polycyclic aromatic rings, such a~
n~phthyl ~nd ~nthr~cyl aromatic ring3, in the linXing 15moieties ~re therefore possible. Fused benzo rin8A
are compatible with the coplanarity of the ~romatic nuclei and, unle~a they are them~elves sub~tltuted, have lil~,'le effect on electronic a~yrnmetry. It is further recognized that R2, R3, ~nd R4 can, ~f 20de~ired~ form with sn Rd ~ubstituent ortho to D a ~ fused ring, prefer~bly of 5 or 6 member ring. For : ex~mple, the amino electron donor moiety in Formula P~ir ll can form with the linking moiety ~ ~ulolidene ring. Numerous other fused rings contsining the 5hetero~tom of the electron donor moiety are po~ible.
However, while within the conte~pl~tion of useful dipole moleculsr structures, fused ring sub~tituent pattern~ are not gener~lly preferred, ~ince they increaqe molecul~r bulk, thereby reducing the 30hyperpolarizability den~ity, while lacking in m~ny in~tanc~ the synthetic convenience of monovalent : sub~tituent~.
The ub~tituent~ Rl and R4 are optionslly ~ubstituted hydroearbon ~ubstituents in all in~tanee~, 35wh~1e the 3ubstitutents R~ and R3 can be hydrogen or optionAlly substituted hydrocarbon substituents, : with one or both mo~t prefer~bly being optionally substituted hydrocarbon ~ubstituent3 Specificslly contemplated form~ of hydrocarbon ~ubstituent~ are ~liphatic hydroc~rbon ~ubstituent~ containing from 1 to about 40 ~prefer~bly 1 to lO c~r~on atom~ end 50ptimal.1y 1 to 6) earbon ~toms -e.g., ~lkyl, alkenyl, ~nd ~llcynyl, including all cyclic form3 thereof;
&romati.c hydroc~rbon ~ubstituent~ containing from 6 to 20 carbon stoms (preferably 6 to lO carbon ~tom~ -i.e., phenyl ~nd naphthyl); ~nd hydrocarbon sub~tituent~ which ~re composite~ of the e ~llphatic ~nd aromatic substituents -e.g., ~lk~ryl, arslkyl, alkaralkyl, ~ralkaryl, etc. The ~liphatic ~ubstituents ~nd ~ub~tituent moietie~ can cont~in : un~atur~tion for 4teric or ~ynthetic convenience. All 150f the hydrocarbon sub~tltuent~ c~n, optionally, themselves be sub~tituted to facilit~te polAr alignment in the transmission medium. Any one or combination of the hydroc~rbon ~ub~tituents can be : sub~tituted with the cros~linking moiety L.
The hydrocsrbon and sub~titute~ hydrocarbon sub~tituents of the electron a~ceptor ~nd donor moieties can be cho~en, if deslred, to enhance the electrvn accepting or donatin8 functions of the electron acceptor ~nd donor moieties, respectively.
i 25~mmett ~igma values of the electron donor ~nd : ~ electron ~cceptor moietie~ ~re u3eful for this : purpo~e, as expl~ined above in connection with the ~election of Ra snd Rd substituents For example, ~: the Hammett si~m~ values of ~ primary amino group ; 30(-NH2~; second ~mlno ~roups, ~uch ~5 alkylamino (e.g., -NHCH3, -NHCH2CH3, and -NH-n-C~Hg);
:~ Qnd tertiary amino group~, such a~ di~lkylamino (e.g , dimethyl~mino~ r~nge from -0.04 for the primary smlno group to -0.83, wlth the ~econdsry ~nd tertiary ~mino 35group~ generally having Ham~et~ 3igma values more ne8ative than -0.20.

~:

- .

' '7 For the moleculsr dipoles to form a crosslinked polymeric m~trix it is nece~sary th~t th~y be linked in polar ali~nment to at lea~t three ad~3cent molecular dipoles. For this to be ~chieved 5e~ch molecul~r dipole requires 8t leask one crosslinking moiety L. Where ~ ~31ngle cro~slinking moiety i~ provided for each molecular dipole, the croq~linking moiety must itself be c~pabte of linking at least three ~d~acent molecular dipoles in order to lOform ~ cros~linked polymeric matrix. A siloxy (SiO3) group i9 ~n example of ~ preerred moiety capable of ero3slinking three ad~cent molecular ~ipoles through oxy (-O-) linkage~. Where two or more cro~linking moietie~ ~re provided, the preEerred 15crosslinking moleties are obt~ined from ~ctivated vinyl groups. By reactlng activ~ted vinyl groups cross~inking moieties ~re produced which form ~
polymeric backbone to which the remainder of the molecul~r dipole is linked ~s a pendant group. By 20providing two or more crosslinking moieties the molecul~r dlpoles ~oin in forming two or more polymerie backbones and hence a crosstinked polymerio m~trix.
The exact form of the molecular dipole 25polymeric matrix chosen will depend to some extent upon the ~pproach taken to form an optieally active tr~nsmission medium. The following pref~rred approRche~ ~re selected in part to show the diversity of forms the molecul~r dipole containing polymeric 30matrix can take.
One appro~ch to forming optically active tr~nsmission layer~ s~ti~fying the requirement~ of the invention cfin be prActlced by producin~ self--a~embled ~ilms. The term "~elf-as3embled" is employed to 35indic~te th&t the film c~n be formed from ~ucce~sive monomolecular l~yers th~t are e~ch qpontaneou~ly ; oriented on deposition. One technique for forming ``` ~ 3~ ~ ~7 optic~lly ~ctive ~elf-a~sembled films s~tisfying the requlrements of this invention can he practiced by modifying the teschings of Saglv U.S. Patent 4,539,C~61. S~giv te~che~ to form lsyers on substr~te~
5by ~equenti~l deposition. A first monomolecular layer is formed by re~ctin~ with or ~dsorblng on the surf~ce of a 3ubstr~te a compound consi~ting o$ ~ hydroc~rbon linXin~ moiety ~oinin~ ~ bonding group Mnd a bonding group precur~or. The flr~t l~yer i~ depo~ited on the lO~ub~tr~te ln ~ ~patiRlly oriented manner with the bonding groups adsorbed or bonded to the substrQte qurfece and the bonding group precur~ors remote from the substr~te surf~ce. After the first l~yer is formed, the ~onding group precur~or~ remote from the ~ubAtr~te surfsce are modified so th~t they can provide bonding sites. A second l~yer can now be formed on the first layer simil~rly ~s the first lsyer i9 depo~ited on the substr~te. A$ter the second layer is formed, the co~ting s~quence can be ~g~in repeated, ~Oif ~eslred, until ~ film of the de~ired thickne~ iq realized.
~; One very signlfic~nt diEference between the elf-~sembled films of thi~ ~nvention and those disclo3ed by Sagiv is that in3tes~ of ~ hydrocarbon - 251inking molety~ ~s ~ught by Sagiv, this invention employs two hydrocarbon moieties, one forming a part of the sulfonyl electron ~cceptor moiety and the other forming a p~rt o~ the electron donor moiety, wherein one of the hydroc~rbon moieties is substltuted with a 30bonding group an~ the other i~ ~ubstituted with ~
bonding group precursor~ The entire molecul~r dipole .~ molecule employed to $orm ~ ~elf-as~embled film c~n be ,: described by Formul~e 15 or 16:

~ 35 tl5) p R
0=S~0 ; lo pl R
e 0=S=0 E
'I 1,,, 20 (16) .
~; ~ B~

O=S~
E
~: D
~ 11 :~ ; 30 B l ~: ~ R
I e~
: ~ ~ O=S~

~: Dl ,~ Pl 3(:~5'~7 ~ 36-where E is ~ linking moiety ~g preYiously desoribed, Dl is ~n electron donor moiety, ~uch ~s -NR2R3 or -XR4, previously described, where ~t 5le~st one of R~, R3, or R4, when present, i5 ~n option~llly ~ub~tituted hydrocarbon group ~s de~cribed above ~urther ~ubstituted with Bl or pl;
B i~ ~ bonding group; ~nd P is a bonding group precur~or.
Of the various bonding groups de~cribed by S~giv, cited above, tho~e which are c~pable of crosslinking ~t le~st three ad~acent moleoul~r dipoles can be employed. Sil~ne moieties, such as trichlorosilaneq, ~re psrticul~rly suited for th~
15purpo~e.
S~giv discloses a large variety of bondin~
group precursors And v~ried techniques for thelr conversion to bonding groupq. Such bondlng group pr~cur~ors and conversion techniques can be employed ~to the extent th~t they are comp~tible with the preservation of th~ molecul&r dipole. In gener~l, however, the dr~coni~n ~ppro~ches (e.g., ozonolysis~
~:~ sugge~ted by Sagiv ~re incomp~tible with preservation of the molecul~r dipole~ of this invention.
In a preferred form pl c~n tske the form o~
9 precursor th~t can be hydrolyzed under relatively mild condition~ to provide a hydroxy functional group. Many of the convention~l techniqueA for forming ~lcohols c~n be employed. For example, when 30the bonding group precur~or ls ~ halide ~ubstituent, ~ thP h~lide can be re~dily di~placed by hydroly~i3 to :~ provide ~ hydroxy ~roup. E~ter, ~midet ~lkylthio, arylthio, ~ryloxy, ~nd alkoxy group~ can ~lso be ~: reAdily hydrol~22d by known technique~ to create ~: 35hydroxy ~ubst1tuent on the hydroc~rbon of the molecul~r dipole.
:

, 13~i7'7 In ~ ~pecifically preferred ~orm of the invention the substr~te chosen for the con~truction of sel$-~s~embled film ~ ~n optically tran~parent siliceou~ support, ~uch ~s quartz or gla~s. Siliceou~
S~upports are Xnown to exhibit hydroxyl groups ~t their surf~ce~. A monomolecular layer of a compound ~ati~fying Formul& 15 or 16 is spread on the ~iliceou3 sub~tr~te. The prefcrred bondlng group ~s -SiC13.
Reaction of the bonding group with the sub~tr~te in l0the presence of wa~er produces ~ fir3t l~yer of the following ~tructure:
pl pl pl I
MD MD MD
--O--si~si~si--O O O
.. ... I
Substr~te where MD represent~ -S02-E-D- defined above in connection with Fsrmulae 15 and 16 ~nd P is prefer~bly ~ bonding ~roup precur~or th&t can be employed to form A hydroxy group by hydrolysi3.
The MD moiety can be oriented with either the electron 5scceptor or donor moiety ne~rest the ~upport.
When the bonding group precur~or is converted to a hydroxy group, a second layer simil~r to the first can be formed on the substr~te. By repeating thi~ ~equence of ~tep~ Any de~ired number of l~yers 30c~n be formed. The following illustrates A preferred self-~s~embled film formed by three succ8a ive ;

` -~3(~77 depo~ition~:
pl p~ pl MD MD MD
I J
--O--S i~S i~S i-- i O O O
I
MD MD MD
--O--S i--~S i~--S 1--I
O O
I I I
MD MD MD
--S i~ i~S i--I
O o o Substr~t2 : In this form of the invention the : crosslinking moietieq L take the form of oxy (-O-) :~: llnX~ges. Note th~t ad~acent molecul~r dipoles share :~ a common oxy linkAge. It is immaterial whether P
;~ ~ in the final l~ayer remain~ a~ a bonding group precur~or or i~ converted to 3 hydroxyl ~roup.
Altho~ugh optically ~ctive tr~n~mi~3ion l~yers ~re useful cont~ining a single aligned MD layer, it is preferr~d to:con~truct optic~l articles according to thi~ invention with at least 50 superimposed MD
yers, most preferably at least a 100 layer~. The layer~ ~uperlmpo~ed can range ~ high ag 5000 or : more.~ In practlce u~u~lly up to ~bout 1000 layera are : laid down to form ~n optic~lly ~ctive tran_mi~sion medlum. Self-as~embly depos~tion teehnique~ are preferred :$or the fabrication ~f optic~lly ~ctive : tr~nsmission films:having thickn~sse~ ranging up to bout 2000A.
: : Where relatively thick optlcally ~ctive lements, such as those gre~ter than Rbout 2000A in thicknes~ and p~rticul~rly those greater than 1 ~m ,`
~, ;
':
':' , .

~L3~ 7 in thickness, ~re desired, forming the optic~lly ~ctive l~yer in ~uccessive monomolecular deposition sequence~ c~n be time consuminX. Therefore ~hicker optic~lly ~ctive elements sccording to the invention 5 ~re preferably conatructed by m~croscopic construction technigues - that is, construction techniques th~t are c~psble of forming msny or ~11 molecular layers of the optically ~ctive element simultanleously an~ therefore do not require repetition a~ ~ functlon of the number 10 of molecular layers.
One preferred m~croscopic construction approach is to pattern (e.g.~ 8pin CPSt or otherwise suitably sh~pa) ~ fluid containing the molecul~r dipole in ~n unordered ~tate, ~lign (pole) the 15 molecular dipoles ln an externally applied electric field, ~nd convert the fluid to a rigid crosslinked polymeric m~trix capable of holding the molecular dipoles in polsr alignment when the extern~l field is no longer present. A number of different variations 20 on thls general appro~ch are possible.
A preferred approsch for schieving macro~copic con truction of an optic~lly ~ctlve trsnami~sion medium i to employ moleculsr dipoles which Rre monomers each cont~ining two or more 25 photopolymeriz~ble substituent groups. Flexible : linkages ~re required in the molecule so that the photopolymeriz~ble ~ubstitutent groups ~re ~llowed freedom of orient~tion while the molecul~r dipole ; remains in pol~r sli~nment with the extern~lly ~pplied 30 electric field. Exemplary forms of molecul~r dipole repeating unit~ derlved from dipole monomers cont~ining two:polymeriz~ble sub~tituent groups ~re illu~trRted by Formul~ P~irs 17 through 28. Dipole monomer~ cont~ining three or four photopolymeriz~ble ~ubstitutent group~ di~fer from tho~e illu~tr~ted only by the number of ~ub~tituent groups pre~ent which ~re : subst~tuted by cro~linking group~.
.~

. ~ 3~?~5~

L _~2_~R3--L
E

L --R2_N+--R3--L
E

. L --R2_N--R3 i 5 I E: - R~--L

: ~ 20 L --R2_N+--R3 . ~ : I 11 a E--R --L
e ~ ~ l g ) -~ ~ 25 L --R2~N--R3 E--Rd_L
.
30 ~ ~ I
, R2 P3 ~R3 d_ ,~
:~

~ ~L3~5~ ~'7 (20) L --R2_N~R3 I
E
OQ=S-=O
Il L --R~--I 1~--R3 E
~---S~O

I .
--L--(2~) D

E--R~ L
O--~S~O
, ~: ~ Rl ~;
' L--~ ,~
'',::: : 1 : ~ D
I~ I
E:--~R~--L
: :~ 3 0 0 S=0 ~:; I 1 ~:
3 5 ~ :

, 3~ a -It2-(22) D

i O~S =0 --L--I

1 0 D~

E Rd~L
O~

--L--(23) D

L --Ra_E--R~--L

D
; 2 5 : L--R~--E--R~
Ae : ~ (:24) D
3 0 ~ : L _~d E--Rd_L
A

:35 D1 ' . ' ' , ~3~5S~j'7 (25) L ~ E--Ra_L
s L --Rd_E--R8_L
13 1 ~ I

6 ) --L~

E--Ra_L
A
, :~ --L--1l 1 : E--R8_L
~ .

; ~ ~ 30 :, 3~SS~

(27) --L--E--Rd_ A
I

--L~
X~
E--Rd_L
(28) _~

R
X
O---S~O ':

._ :: 30 i 4 :
:
:: : 11 : E:
O~S

~ R
--L--~3~5~

where A, E, D, snd L ~re ~ previou~ly defined ~nd Ra ~d Rl R2, ~3, ~nd R4 sre moieties satisfyin~ the requirement~ previou31y 5de~cribed, but in thi in~tance when L substltuted urther cho~en from smong tho~e mc)ieties whieh ~re cspPble of scting 8~ flexible sp~cer~ allowlng the precur~or of the photocro~linkin~ moiety to orient itself 3pati811y in relstion to the remsinder of the dipole monomer prior to polymeriz~ltion.
In a preferred form the flexible spscer ls an option~lly suhstituted hydrocarbon moiety, such as ~n alkylene group, containing from 2 to 10 carbon atom~, prefer~bly 4 to 8 carbon atom~. While the ~lkylene : 15chsin link c~n be extended to 20 or even 40 carbon atom~, it i~ generally preferred to re~trlct the si~e of the sp~cer moiety to ~void reduction of the hyperpolarizability den~ity. In ~ ~pecifically preferred form the sp~cer moiety i~ a -(CH2)r-20group, where r i3 2 to 109 preferably 4 to 8.
In a preferred form form the photocros~l1nk-ing moiety L I~ derived from an ~ctivated vinyl group to ~ati~fy Formula 29:
: ~2~) HCH
--Ac--C--R
where Ac i~ ~n ~ctivating moiety ~nd R i~ hydrogen or a lower ~lkyl group of from 1 to 6 csrbon stom~ preferably hydrogen or methyl.
In 8 3pecific preferred form of the invention the activ~tin~ moiety i~ a c~rboxy -C~O)O- moiety.
In ~ 3pecific preferred form of the invention ~:~ the cro~linking moiety L ~ti~fies Formula 30:
:

(30~

O HCH
~I 1 5 ----O----CC-R

where R iS 8~ previou~ly defined.
In ~ ~pecificslly preferred form of the invention the cros~linking moi~ty ~s ~n scryl~te or meth~crylate moiety .
The dipole monomer~ are liquid~ Bt rOQm temperature th~t can be placed in a mold or ca~t on a ~upport surfQce to provide the desired geometric fDrm of the op~icslly active tran~mission medium to be produced. Upon pl~cing the liquid in it~ de~ired confi~urstion in a electrical field, the dipole monomers arrange themselve~ in polAr alignment with the applied field. Thereafter, with the field still applied, polymeri~ation can be initi~ted to produce the desired cros~linked polymeric m~trix.
Polymerization can ~e induced thermally by hesting the poled dipole monomers. However, ~lnce heating increaaes the kinetic motion of the dipole monnmer~ and; therefore tend~ to reduce pol~r alignment, it~is preferred to rely on electromagnetic r~diation to initi~ts~polymerizstlon. By employing more highly energetic forms of electromagnetic radi~tiQn, ~uch ~s ~horter wavelength ultraviolet radi~tion, photopolymerization can be achieved in the sb~ence of ~ polyMerization ini~i~tor.
It is:preferred to ach~eve photopolymeriza-tion by exposure of the medium containing the pol~r ~ligned (poled) dipole monomsrs to vi~ible light or ne~r ultraviolet (290 to 390 nm) r~iation. Any convellient photopolymeriz~tion initi~tor c~n be employ for thi~ purpo~e. In ~ ~pecific~lly preferred ~orm two coinitiator3~ on activRtor and a photo~en~1tizer . ~3 ~ ~ ~7 ~re employed in combin~tlon. Any of the photo-sensitizer ~nd initiator~ disclo~ed in Mol~lre U.S.
Pstent 4,322,490, Molair et al U.S. Patent 4,619,B90, ~nd Scozzafava et ~1 V.S. P~tent *,485,161 can be 5employed in the practice of this :Lnvention.
Specht and FRrid U.K. 2,083,832A discloses ~s coiniti~tors zinium activstors and amino-~ubstituted 3-ketocoumsrin and nsphthothi~zole merocyanine photoqensitizers which are useful in promoting photocrosslinking in the ne~r VV ~Ind blue portion3 of the spectrum~
Preferred coinitiators for photocrosslinking by expo~ure to electrom~gnetlc r~di~tion hf w~velengths lon~er than 430 nm ~re the ~pecific sub~ect matter of commonly ~s~igned, copending filing~, F~rid et al U.S. Patents 4,743,528, 4,743,529, 4,743,530, and 4,743,531. F~rid et 81 teaches to employ ~zinium s~lt ~ctiv~tors in combln~tion with dye photosensitizers. The ~zinium 20salt ~ctiv~tors can take ~ny convenient conventional form. The ~zinium ~ctivetor~ di~closed by He~eltine et al ~nd Jenkins et 81 U.S. Rei~sue Patents 27,922 and 27,g25, Specht ~nd F~rid U.K. 2,083,,832A, And ~ese~rch ~isclosure, Vol. 200, ~ec. 1980, Item ~0036, :~ 25cited sbove, provide ~ variety of examples of useful :- ~zinium ~ctivator~
The azinium ~ctivstor~ include ~n szinium nucleu~, ~uch as 8 pyridinium, diazinium, or triazinium nucleu~. The ~zinium nucleus can include ~one or more srom~tic rings, typically carbocyclic srmatic rings ~ fu~ed with An ~zinium ring . In other word~9 the szinium nuclei include ~uinolinlum, i~oquinolinium~ benzo~iazinium, and n~phthodiazonium nuclei. To ~chieve the highest ~tt~inable ~ctiv~tion 35efficiencie~ per unit of weight it i~ preferred to employ monocyclic ~zinium nuclei.

. . .
.
.

~3~

-4~-The ~zinium 8ctlv8tors include a quaternizing ~ub~tituent, ~hich is prefer~bly ~n oxy ~e.g., alkoxy or sryoxy) or ~cyl radical cont~lning from 1 to 18, prefer~bly 1 to 8 carbon ~tom3. The highe~t sctivity 5~zinium ~81t5 ~re those con~aining ~n oxy qu~ternizing ~ub3tituent contRSning 1 or 2 c~rbon atom~. Other substituent~ to the ~zinium ring ~re not require~, but csn be present.
The dye photosensitizers can be ~elected from ~mong any known dye cla~, provided they exhib~t 9 reduction potential which in relation to that of the ~zinium activator is ~t mo~ 0.1 volt more positiYe~
Among specific~lly contemplated dye clas~es from which dyes c~n be selected ~re coum~rin (including ketocoumarin ~nd ~ul$onocoum~rin) dye~, merocy~n~ne dye~, merostyryl dyes, oxonol dyes, ~nd hemioxonol dyes. Dyes from ea~h of the foregoing cl~ses all csntsin a keto group in the blue ~bsorbing chromophore ~nd ~re ~11 therefore designsted keto dyes. In 20sddition, it i~ a specific recognlt~on of thi3 invention thst a dye photo~en~itizer usefu~ in the pr~ctice of thi~ invention need not ~e ~ keto dye.
That is, a keto 8rouP in the blue absorbing chromophore of the dye is not es~enti~l. Non--keto dyes embrace a v~riety of dye clssses; including non-keto polymethine dyes, rhodsmine dyes, anthracene dyes, ~cridine dye~, ~niline dyes~ ~nd ~zo dyes.
Non-keto polymethine dyes lnclude cyAnine, hemicyan~ne, ~nd ~tyryl dyes.
In one preferred form of the invention the dye photo~en~itizer~ ~re chosen from the polymethine ~; dye cla ~ which includes the cy~nine~, meroeyanines, : complex cyanines ~nd merocy~nines ~i.e., tri-, tetrs~ and poly-nucle~r cyanine~ ~nd merocy~nine~), 35oxonol~, hemloxonol~, styryls, merostyryls, And ~treptocyanines.

.

'7 ~9-The cyanine dye~ includ~, ~oined by a methine linksge, two ba~ic heterocycllc nuclei, ~uch ~3 ~zolium or Rzinium nuclei, for ex~mple, those derived from pyridinium, quinolinium, isoquinolinium, 5oxazol:~um, thiazolium, ~elenaæolium, indflzolium, pyrs~o:Lium, pyrrolium, indolium, 3H-indollum, imidszol ium9 oxRdiazolium, thiadioxazolium, benzoxazolium, benzothiszolium, ~enzoxelen~zolium, benzotellurRzolium, benzlmidazolium, 3H- or lH-benzoindolium t naphthoxszollum, n~phthothiazolium, naphtho~slenazolium, naphthotellur~zolium, carbazoliumg pyrrolopyridinium, phenanthrothi~zolium, snd ~cenaphthothiazolium qusternary ~slts.
ExemplRry of the ba~ic heterocyclic nuclel 15&re those ~ati~fying Formulae 31 and 32.
; Formulfl_31 i-- Z--l =C--( L=L )X--N--Rq ~_ _ Z _ _ ~C--~ L--L ) --N --Rq , . X
Formula 32 I- - Q ~
2 5 --C=L--( L----L ) X--N--R
I

(L L~x N R
30where Z repre~ent3 the elements needed to complete a : cyclic nucleu~ derived from ba~ic heterocyclic : ~ nitrogen compound~ ~uch ~ oxazollne, oxszole, benzoxazole, the n~phthoxazoles (e.g., n~phth[2,~-d]-350x~zole, naphth[2,3-d]ox~zole, and n&phthtl,2-d]ox-azole), ox~diazole, thiazol~ne, th~a201e, benzothi-azole, the nsphthothiazole~ (e.g., naphthot2,1-d]thi-~ ~ J ~

~zole), the thi~zoloquinolines (e.g~, thl~zolo[4,5-b~-quinoline), phensnthrothiszole, ~cen~phthothiszole, thiadioxszole, ~elen~zoline, selenazole, benzo~elen-azole, the naphthoselen&zole~ (e.g., n~phtho[l,2-d]-5selenazole), benzotellurazole, na]phthot~llur~zoles (~.8-. n8ptho[1,2-d3tellur~zole), imid~zoline, imidazole, benzimidazole, the naphthimidazoles (e.g., n~phth~2,3-d~imid~zole3, 2- or 4-pyrld~ne, 2- or 4-quinoline, 1- Dr 3-i~oquinoline, benzoquinoline, 3H-ind41e, lH- or 3H-benzoindole, ~nd pyrszole, which nuclei may be ~ub~tituted on the ring by one or more of a wide variety of ~ub~tituent~ ~uch a~ hydroxy, the h~logen~ (e.g., fluoro, chloro, bromo, and iodo), alkyl groups or sub~tituted ~lkyl groups (e.g., methyl, ethyl, propyl, isopropyl, butyl, octyl, dodecyl, octsdecyl, 2-hydroxyethyl, 3-sulfopropyl, carboxymethyl, 2-cyanoethyl, snd trifluoromethyl), aryl group~ or sub~tituted aryl groups (e.g., phenyl, l-naphthyl, 2-naphthyl, 4-~ulfophenyl, 3-carboxy-20phenyl, ~nd 4-biphenylyl), ar~lXyl group~ (e.g., benzyl ~nd phenethyl~, ~lkoxy groups (e.g.~ metho~y, ethoxy, ~nd i~opropoxy), ~ryloxy groups (e.g., phenoxy ~nd l-n~phthoxy), alkylthio groups (e.g., methylthio and ethylthio), ~rylthio group~ (e.g., phenylthio, 25E-tolylthio, ~nd 2-naphthylthio~, methylenedioxy, cyano, 2-thienyl, styryl, amino or substituted aminD
groups (e.g., anilino, dimethyl~mino, diethylamino, ~nd morpholino), acyl groups, (e.g., formyl, acetyl, benzoyl, ~nd benzenesul~onyl);
3~ Q repre~ents the elements needed to co~plete a cyclic nucleus derived from ba~ic heterocycllc nitrogen compounds such a~ pyrrole, indole, carb~zole, benzindole, pyra~ole, indazole, and pyrrolopyridine;
R~ repre~ents ~lkyl group~, ~ryl group~, ~lkenyl 35groups, or aralkyl groups, with or wlthout ~ub~tituent~, ~e.g~, carboxy, hydroxy, sulo, alkoxy, 8ul fato, thio~ulfato, phosphono, chloro, and bromo SS ~

~ub~tituent~;
L i~ in each occurrence independently ~elected to repre~ent a ~ubstltuted or un~ub~tituted methine group--e.g., -CR5- groups, where R5 repre~ent~
shydrogen when the methine group is unsub~tituted ~nd most commonly repre~ents ~lkyl of from 1 to 4 carbon atoms or phenyl when the methine ,group i5 ~ub~titute~;
and x is 0 or 1~
Cyanine dye~ can contain two hPterocyclic nucle~ of the type ~hown in Formul~ 16 ~oined by a methine link~ge containing ~n uneven num~er of methine group~ or c8n csnt~in a heterocyclic nucleus ~ccording to each of Formulae 16 ~nd 17 ~oined by a methine inkage containing ~n even number of methine group~, where the methine ~roup~ c~n take the form -CR~
de~cri~ed above The gre~ter the number of the methine groupA linking nuclei in the polymethine dyes in gener~l and the cy~nine dyes in particul~r the 20longer the sbaorption wsvelength~ of the dyes. For example, dicarbocyanine dyes ~cyanine dyes containing five methine group~ linking two basic heterocyclic nuclei) exhibit longer ~b~orption w~velengtha th~n c~rbocy~nine dyes ~cyanine dyes containing three .~ 25methine group~ linking two bs~ic heterocyclic nuclei) which ln turn exhibit longer absorption wavelength~
thsn simple cyanine dyes (cyanine dye~ contalning 8 single me~hine group linking two ba~ic heterocyclic -~ nuclei). Carbocyanine and dic~rbocyAnine dyes are 30longer wavelength dyes while ~imple cy~nine dyes ~re ~ typic~lly yellow dyes, but can exhibit ab~orption : mexim~ up to ~bout 550 nm in waYelength with proper choice of nuclei ~nd other component~ c~peble of b~thochromically ~hi~f~ing ~bsorption.
~; 35 One of the techniques for bathochromically ~hifting the ~bsorptlon maxima of polymethine dye~ in :~ genersl ~nd cy~nine dye~ in p~rticul~r i~ to lnclude i in the methine link~ge ~n oxoesrbon bridging nucleus.
Exemplary oxoc~rbon bridging nuclei can tQke any of the forms indicated by Formul~ 33.
Formula 33 ~I 11 (C )~'C-\ D
G~

I

o o ,c_(C~y~
1 s ~C/

wherein y is the integer 0, 1, or 2.
Merocy~nine dye~ link one of the cyanine dye 20type ba~lc heterocyclic nuclei descrbed above to ~n ~cidic keto methylene nucleus through ~ methine link~ge ~ de~cribed ~bove, but cont~ining zero, two, or ~ higher even number o~ methine group~. Zero ~ methine dye~, those containing no methine groups in : 25the link~ge between nuclei, exhibit a double bond : link~ge bet~een the nuclei in one resonsnc~ form ~nd a ~ ~ingle bound link~ge in another reson~nce form. In : either reson~nce form the link~ge site~ in the nuclei : ~re formed by methine groups forming ~ psrt oÇ e~ch 30nucteus~ Zero me~hine polymethine dyes sre yellow : dye~.
Exempl~ry acidic nuclei ~re those whi ch ~ti~fy Formul~ 34.
Formuls 34 ~: 35 0 Gl ~G~
.

-where Gl repre~ents ~n ~lkyl ~roup or ~ub~t~tuted ~lkyl group, ~n aryl or substituted ~ryl group, an sr~lkyl group, ~n alkoxy group, ~n ~ryloxy group, ~
hydroxy group, an amino group9 or 8 sub3tltuted amino ~roup, wh~rein exempl~ry ~ub~tituents c~n take the v~riou~ form3 noted in connection with Formul~e 1 snd 2;
G2 c~n represent any one of the group~ ted for Gl and in sddition c~n repre~ent ~ cy~no group, ~n ~lkyl, or ~ryl~ulfonyl group, or ~ group represented by -C-Gl, or G2 t~ken tQgether with ~1 o can repre~ent the element~ needed to complete a cyclic ~cidic nucleu such a~ tho~e derived from 2,4-ox~zoli-dinone ~e.g., 3-ethyl-2,4-ox~zolidindione)~

2,4-thi~zolidindione ~e.g., 3-methyl-2,4-thiazolidin-dione), 2-thio-2,4-oxa201idindione (e.g., 3-phenyl-2-20thio-2,4-ox~zolidindione)9 rhodanine, ~uch as 3-ethylrhodsnine, 3--phenylrhodanine, 3-~-dimethyl--~minopropyl~rhod~nine, snd 3-c~rboxymethylrhodanine, hyd~ntoin (e.g., 1,3-diethylhyd~nto1n ~nd 3-ethyl-1-phenylhydantsin~, 2-thiohyd~ntoin (e.g., 1-ethyl-3-5phenyl-2-~hiohydantoin, 3-heptyl-1-phenyl-2-thiohyd~n-~; toin, and aryl~ulfonyl-2-thiohyd~ntoin), 2-pyr~zolin-S-one, ~ueh a~ 3-methyl-1-phenyl-2-pyrszolln-5-one, 3-methyl-1-(4-cRrboxybutyl)-2-pyr~zolin-5-one, ~nd 3-methyl--2-(4-sulfophenyl)-2-pyrazolin-S-one, 2-i~ox~zolin-5-one (e.g., 3-phenyl-2-i~oxazolin-5-one), 3,5-pyr~zolidindione ~e.g., 1,2-diethyl-3,5-pyrazolid~ndione ~nd 1~2-diphenyl-3,5-pyr~zolidin-dione), 1,3-ind~ndione, 1,3-diox~ne-4,6-dione, 1,3-cyclohex&nedione, barbituric acid ~e.g., 351-ethylbarbituric scid and 1,3-diethylb~rbituric ~cid), ~nd 2-thiob~rbituric aeid (e~g., 1,3--diethyl~

2-thiob~rbiturlc ~cid ~nd 1,3-bi~2-methoxyethyl)-2-.

, ' ~

:~3~S~

thiobarbiturio ~cid).
Useful hemicyanine dyes are e~3entially similar to the merocyanine dyes described ~bove, differlng only in ~ubstituting for the keto methylene 5group of Formuls 34 the group ~hown below in Formuls 35.
Formul~ 35 lo ~4 where G3 and G4 may be the ssme or different ~nd may repre~ent alkyl, sub~tituted slkyl, æryl, sub~tltuted ~ryl, or ~r~lkyl~ a3 illu~trated for ring substituents in Formul~ l or G3 ~nd G4 taken together complete a ring ~y~tem derived from a cyclic secondary ~mine, such as pyrrolidine, 3~pyrroline, piperidlne, piper~zine (e.g., 4-methylpiperazine and 4--phenyl-piper~zine), morpholine, 1,2,3,4-tetr~hydroquinoline, dec~hydroquinoline, 3-azabicyclo~3,2,2]nonane, indoline, azetidine, and hexahydro~zepine.
Useful hemioxonol dyes exhibit a keto methylene nucleus as ~hown in Formuls 34 and a nucleus : ~ shown in Formuls 35 Joined ~y a methine linkage 8~
: previou~ly described containing one or a hi~her uneven 5number of methine groups.
U~eful merostyryl dyes exhibit s keto .~ methylene:nucleus as ~hown ~n Formula 34 ~nd a nucleus as shown in Formula 36 ~oined by ~ methine linkage a3 30described ~bove containing one or a higher uneven number of methine groups.
~ormula_36 35where G3 and G4 ~re as previously defined.

' ~3~ 7 rhe cysnine, merocy~nine, hemicyanine, hemioxonol, ~nd mero tyryl dyes deacribed ~bove ~re intended to be illustrative of the ~impler ~tructur~l ~orms o~ useful polymethine dyea. It i~ generally 5recognized that substituents c~n 'loin the nuclei ~nd methine link~ges to ~orm ~dditional cyclic structures. Further, the dye~ c~n cont~in three or more nuclei. For exsmple, by substituting a merocysnine dye in itc methine linkage with ~ ~econd b~sic heterocyclic nucleus o the cy~nine dye type an allopolar cy~nine dye can be ~ormed. Further, the vsrisus ~ub~ituents not forming ~ part o~ the dye chromophore can be v~ried a2 desired to tailor dye phy~ic~l properties, psrticul~rly hydrophob~city ~nd hydrophillicity, to suit the particul~r film forming component~ employed. By choosing ~s the aliph~tic moieties of the dyes hydrocarbon group~ h~ving more carbon atoms (e.g~ from about 6 to 20 csrbon atoms3 th~ dyes csn be rendered more oleophilic while hydrocarbon groups containing fewer number~ of csrbon ~toma (e.g., 1 to 5 csrbon ~toms) snd p~rtlcularly ~:~ those be~rin8 pol~r ~ub~tituent~ render the dyes more hydrophilic. The ~romatc moieties of the dyes : typically cont~in from 6 to 10 carbon atoms.
When employing ~s eoinitlators ~æinium activator~ and dye photosensitizers, the azinium activ~tor is preferably present in a concentrstion of from 2 X 10 5 to 25 X 10 5, most preferably from about S X 10 5 to 20 X 10 5, mole per gram of the 30binder precursor.
The photosensitizer c~n be preaent in ~ny concentrqtion cap~ble of increasing the response of the binder precur~or compo~ition including the ~ctiv~tor to visible light. Whilc the photosensitizer 35concentr~tion c~n ~ry widely, it i5 gener~lly contempl~ted to employ photo~ensitizer in concentra-tions rAnging from ~bout 5 X 10 7 to 1 X 10 4 mole .

~ ~3~

per gr~m of binder precur~or. Pr ferred photG-~ensitizer concentrstions 8re in the r~n8e of from l~ 6 to 5 X lO 5 mole per gram of binder precursor, with optimum concentr~tion~ gener~lly being sin the range of from about 2 X lO ~ to 2 X lO 5 mole per gr~m of blnder precursorO
Upon polymeri2~tion the photocrosslinking moieties Ll ~re converted to cro~slinking moletie~ L
which form polymeric b~ckbone3. Since e~ch molecular dipole includes ~t least two cro~slinking ~loietie3 L, a rigid crosslinked polymeric matrix i~ cre~ted.
One of the significant adv~nt~ges of the pre~ent lnvention i~ the high hyperpol~rizability den~itie3 which can be realized. The optic~lly active transmi3sion medium can consist entirely of repeating unit~ formed by the molecul~r dipole~. In the preferred form of the invention only very ~m~ll r~3idues of polymeriz~tion initiator~ are also present. Their concentrations are u~ually ~o ~mall, 20however, ~s to h~ve no significsnt effect on the optical or physic~l properties of the optic811y active tr~n~mission medium.
While not required or preferred, it i~
recognized~ ne~ertheless, that the optic~lly ~ctive 25~r~n~mi~sion medium can, if de~lred, contain materi~ls other th~n the molecular dipole repeating units. For exsmple, to f~cilitste spin csstlng of the dipole monomer~ or otherwi~e improve rheologic~l properties, minor amount~ of ~nothPr m~terial such a~ a 801vent 30u~ed to reduce vi~cosity or 8 lineer polymeric binder u~ed to lncreese viscosity c~n be present. A liquid ~olYent wheh incorpor~ted can usu~lly be removed by evaporation before polymerization. Line~r polymeric binder~ c~n be retained to form polymer blend~, which 3sbe cho~en to tailor the physical or optical proE~erties of the tr~nsmi~ion medium for optimum utility. To minimi~e reduction of hypetpol~rizability den~itie~

attribut~ble to the incorpor~tion of ~ linear poly~er, the linear polymer can it~elf cont~in moleculsr dipnle~ which can be poled~
It is 8190 recognized that other photo-5~ctiv~ted monomer~ can be incorpor~ted to formdifering repeating units in the cro~sllnked polymeric mstrix, if de~ired. Becau3e of their ~uperior properties, including except~on~lly high level~ of optic~l trsn~p~rency within the visible portion of the ~pectrum ~nd ea~e of h~ndling snd polymerizing, preferred binder precur~ors ~re a,K-ethylenic~lly un~aturated monomers. Vseful ,8-ethenic~lly unsatursted monomer~ are derived from:
1. polyfunctlon~l ~rom~tic or ~liph~tic Acids ~uch 8~
1,3,5-benzenetricarboxylic acid, 1,4-benzenedicar-boxylic scid, 1,3-benzenedic~rboxylic acid, 1,3-nsphth~lenecsrboxylic acid, 1,2,4~benæenetri-c~rboxylic ~cid, 1,2-benzenedicarboxylic ~cid, 1,2,3-benzenetricArboxylic ~cid, 1,2,4,5-benzene-tetrscarboxylic acid, 1,2,3,5--benzenetetr~c~r-boxylic scid, 1,4-cyclohexanedicarboxylic ac1d;
1,3-cyclohex~nedicarboxylic ~cid, 1,3,5-cyclo-hexsnetricar~oxylic acid, 1,2-cyclohexaned1car-~boxyllc E}cid, lf~,~cyclohex~netric~rboxylic ~cid, 1,2,3-cyclohexanetric~rboxylic acid, 1,2,4,5-:~ cyclohexsnetetr~carboxylic ~cid, 1,2,3,5-cyclo-hexanetetr~carboxylic acid, 1,2,4,5-cyclohex~ne-tetracarboxylic ~cid snd their deriv~tives.
2. poly~unctional srom~t~c or aliphatic alcohols ~uch a~ 1,2,3-b~nzenetriol, 1,2,4-benzenetriol, 1,3,5-~en~enetrlol, 1~2--benzenediol, 1,3-~enzene-diol, 1,4-benzenediol, 1,2~3~~yclohexanetrlol, ~-~ 1,2,4-cyclohexanetriol, 1,3,5-cyclohexanetriol, 1,2-cyclohex~nsdiol, 1,4-cyclohexanediol.
3S3- polyfunctional polynuclesr ~romatic or aliphatic alcohol~ such as hydrogensted ~isphenol A, bisphenols wlth long ch~in bridges such a~

butylene, heptylene, hexylene, oct~decylene and the like.
4. polyfunctional polynuclear ~rom~tlc or ~llphatic ~cid~ 3uch ag phenylindanedicsrboxylic ~cid, hy~rogenated phenylindanediearboxyl~c ~cid, 4,4~ opropylidened~benzoic ,~cid, 4,4'-i~o-propylidenedicyclohexanoic ~cid.
5. snd other polymerizabl~ cros~llnk~ble monomer~
th~t csn be coated with or without ~ solvent and cros~linked to yield an ln~oluble film with suitable electric~l prspertie~ ~or use 8~ a barrier lsyer.
The polymerizable cro~slinkable m~nomer~
prepsre~ from the aboYs polyfunctional nuclei, c~n be mixed in certsin proportion with monofunctional polymeriz~ble monomer~ to control certain phy~ical propertie~ ~uch ~s vi~co~ity, flexiblllty, curing peed, and sdhe~ion.
U~eful a,~-ethylenic~lly unsaturated 0monofunctlon~1 monomers include benzoyloxyethyl ~cryl~te, benzoyloxypropyl ~crylate, benzoyloxypentyl ~cryl~te, benzoyloxybutyl acryl~c, ben~oyloxyhexyl ~ scryl~te, benzoyloxyethyl meth~crylate, benzoyloxy-: propyl methacrylate, benzoyloxybutyl methacryl~te, : 25benzoyloxypentyl methacrylate and benzoyloxyhexyl : meth~crylate, phenyl acrylate, phenyl meth~crylst~, cyclohPxyl ~eryl~te, cyelohexyl methacrylate, : cyclohexyloyloxethyl ~cryl~te~ cyclohexyloyloxypropyl ~crylate, cyclohexyloyloxyhexyl ~cryl~te ~nd 30combin~tion~ of these monomers.
: ~ Psrticulsrly preferred a,B-ethylenic~lly un~etursted monomer~ ~re tho~e h~ving c~rbonyl-: :cont~in:~ng ~ubstltuents. In e speci~ic~lly prefe.rred form ~uch monomer~ ~tisfy Formuls 37:
35(17) 0 0 il ~I
R ~ff~--(}R2~ OC--C3t:H2 ~ t .~ .

3~

wherein R repre~ents ~ cyclo~liph~tic (e.g., cyclohexyl~
or ~n 8rOm~ltiC (e.g., nsphthyl or phenyl) group;
Rl represent~ hydrogen or alkyl of from 1 to 6 5 csrbon atom~ ~ preferably hydrogen or methyl;
R~ repesents ~lkylene of 1 to 20 carbon ~toms ~prefer~bly 1 to lO carbon atom~) 9 or --CH2CH2 ~OCH CH )r;
r i~ 1 to 20, prefer~bly 1 to 6;
1 0 s i~ O or l; ~nd t i~ 1 to 6, preferebly 2 to 4.
Repre~entative example~ of ~uch monomers ~re presented in Table I below.
Tsble I
O O o 1. CH2=HC--~CH ~C\ ~ ~CH2~5--CH=CH
i1 ~./
C=O O

~(CH~ ) --O--C--CH=CH2 O O
2. CH =HC--C~CH2~ ~ ~ ~ /C~CH2~C--HC--CH
t h 7~ ~0 . ~ i '; C~
~(CH2~6~C CH=CH2 O O O O
Il i1 11 11 3. CH2----HC--C~CH ~C~ ~~ /C~H~C--CH=CH
J
~-~ 3 5 C=O
. O O
(CH2)3~C--CH~ 2 L3~5~

O O O O
~I il 11 t~
4. CH =C--C~}(CH~)r~C~ / ~ ~C~(t:H~r~f::~C=C~2 o=c~(cH2 )r~ C~Ha E~
Rl -- H ~ CHa;
10 n = one to 6.
Q
Il 11 ' R C~ \~ T / ~
2 1 (CH2)r~1l C (}(CH )r--()~C C----C~i Rl O o R
R = H, CH;
n = one to 6.
1~ / _ ~ ~ S ~-~C--CH CH

: ;~ 3 --/ ~Cll,~" ~ --/
CH

O O
30 1~
: ~. R --O--C~ ~C~}R3 C~R, ~ 1 ~ 3 5 0 :~ : Rl = H~ CH~;
r = 1 to 10;

E~3 ~ CH2CH2~~ H2C~12)n--~C--C~C:H2 -Sl-To ~vo~d dissipstion of the high hyper-pol~rizAbility den~ities afforded by the pre~ent invention, which tran~l~te into high second order pol~riz~tion ~u3ceptibilitie~, molecul~r dipole~ in se~ch instsnce form ~t least 50 percent by weight, prefer~bly at least 70 percen~, ~md optim~lly ~t least 90 percent, of the opticslly actlve tr~n~ sion medium.
Example~
The invention csn be better appreci~ted by reference to the following specific embodiment~ of the invention:
~xam~le 1 Y~ =b~go~ n~ L-- 91~
A mixture of freshly di~tilled ~nillne (93 g, 1.10 mol), pot~ssium csrbon~te (304 g, ~.2 mol), 6-chloro-1-hex~nol (300.0 g, 2.2 mol), ~nd 500 mL of ~-butAnol wa~ he~ted at reflux for ~2 hours under nitrogen with vigorou~ stirring. After cooling and filtering, the but~nol w~ evApor~ted ~t reduced pressure to lesve a t~n oil. The oil was frsctionally distilled in v cuo, yielding 205 g (70%) of Al as ~colorles~ oil, bp 195-225C (0.15 nm).
: lH NMR (300 MHz, CDC13) ~ 1.35 (m, BH~, 1.54 : (m, 8H), 2.75 (br 9, 2H), 3.22 ~t, 4H), 3.56 (t9 4H), 256-61 (m, 3H), 7.18 (t, 2H).
Example ~ N,N-Di-~6-~cetoxyhexyl~aniline ~A2~
To ~ ~tirred solution of N,N-di-~6--hydroxy-hexyl)~niline (A~ ~205 8. 0.70 mol) ~nd pyridine ~133 g, 1.7 mol) W83 added scetic anhydride (171 g, 301.7 mol) dropwise ~t room temperAture. After the initial exothermic re~ction ha~ ~ub~ided, the ~tirred ~olution was he~ted ~t reflux for 4 hours. After cooling, the ~olution W8~ poured onto 503 g of lce ~nd the resulting mixture WQ~ extracted with four 250 mL
3sportion~ of dichlorometh~n~. The combined org~nic :extr~ct~ were wA~hed three time~ with 250 mL of water, ~nd dried over ~nhydrou~ sodium sulf~te~ The ~olvent was removed at reduced pressure and the resulting brown oil was fractinally distilled in vacuo to produce 236 g (90%) of A2 as a slightly yellow oil, bp 220-230°C (0.15 mm).
1H NMR (300 MHz, CDCl3) .delta. 1.25 (m, 8H0, 1.47 (m, 8H0, 1.86 (s, 6H), 3.12 (t, 4H), 3.89 (t, 4H), 6.46 (m, 3H), 7.03 (t, 2H).
Example 3 4-[Dl-(6-acetoxyhexyl)amino]benzalde-hyde (A3) N-N-Dimethylformamide (DMF, 250 mL) was added dropwise with stirring under nitrogen to phosphorous oxychloride (115 g, 0.751 mol) at 0°C. The resulting orange solution was stirred for 2 hours, then a solution of 236 g (0.626 mol) of N,N-di-(6-acetoxy-hexyl)aniline (A2) in 250 mL of DMF was added slowly.
The reaction mixture was stirred under nitrogen for 1 hour at 0°C and then for 6 hours at 80°C. After cooling, the solution was poured onto 500 g of ice plus 200 g of sodium acetate, and the resulting mixture was extracted with dichloromethane (4 x 250 mL). The combined organic extracts were washed four times with 250 mL portions of water, dried over anhydrous sodium sulfate, and then concentrated at reduced pressure to produce a light brown oil. The oil was fractionally distilled in vacuo to yield 192 g (76%) of A3 as a gold oil, bp 220-260°C (0.007 mm).
1H NMR (300 MHz, CDCl3 .delta. 1.39 (m, 8H), 1.63 (m, 8H), 2.04 (s, 6H), 3.35 (t, 4H), 4.07 (t, 4H), 6.64 (d, 2H), 7.70 (d, 2H), 9.70 (s, 1H).
Example 4 4-Nitrobenzyldiethylphosphate (A4) A two necked flask equpped for distillation was charged with 77 g (0.46 mol) of triethylphosphite and heated to 60°C. 4-Nitrobenzylbromide was added in small portions with stirring. A vigorous reaction ensued and the liberated bromoethane was continuously distilled from the reaction flask. After addition if the bromide was complete, excess (approximately 20 g) :~3~5~

triethylphvsphite we~ sdded 910wly to ensure complete conver~ion. The resulting brown oil was c~uti~u~ly di3tilled in v~cuo to yield 115 g (91~) of A4 gold oil 9 bp 155~C (0.15 mm).
H NMR (300 MHz, CDG13 ~ 1.26 ~tp 6H), 3.2S
(d, 2H~, 4.05 (dq, 4H~, 7.48 Sdd. 2H)3 ~.13 (d, 2H).
Example 5 4'~Di-(6-hydroxyhexy~s _ o-4-nitr~-stilbene ~A5~
To a stirred suspen~ion of 7.40 g of 60%
lOsodiu~ hydride di~persion (0.185 mol3, 5000 g ~0.123 mol) of 4 ~di-(6-~cetoxyhexyl)~mino]benz-aldehyde (A3) and 150 mL of dry, fre~hly di~tilled : 1,2-dlmethoxyethsne (DME) under nitrogen ~t room temper~ture w~s ~ded 37.1 g ~0.136 mol) of l54-nitrvbenzyldiethylphosphonate ~A4~. The mixture immedi~tely turned dark red. After the initial exothermic reaction had subsided, the stirred mlxture was heated at reflux for 4 hours under nitrogen, then cooled ~nd poured onto S00 g of ice. The diAcetate ~0 Sep~rAted 89 a red oil, which W~3 eollected by ~:: extractin~ with ethyl ~cetate (4 x 250 mL), drying the :~ combined extracts over ~nhydrou~ ~odium sulfste, And concentr~ting ~t reduced pre~ure. The ~cet~te protectlng group~ were hydroIyzed by refluxing the oil 25ln ~ mixture of 10 mL roncentr~ted hydrochloric ~cid, 100 mL of eth~nol, and 90 mL of water for 16 hours.
After cvoling, he solutlvn was neutralized with ammonium hydroxide, and ~ deep red solid separated.
The produot W~9 filtered, w~hed thoroughly with 0w~ter, ~nd dried. After recryst~lliz~tlon from eth~nol, 27.4 g ~50~) of AS ~ vbt~ined, m.p.
126.5-128.5 ~
'H ~MR (300 ~Hz, CDCl3) ~ 1.41 (mJ
lOH), 1.60 (m, 3H), 3~31 (t, 4H), 3.66 (t, 4H), 6.63 3s(d, ~H), 6.89 (d, lH~ 7.19 (d, lH), 7.41 (d9 2H), 7.S5 (d, 2H~, 8.16 (d, 2H).

: ~:

.

' ~L3~15~

Ex~mple 6 N,N Di-~2-~cetoxYethyl)~niline (A6 2,2'-(Phenylimido)dleth~nol (100 g, 0.552 mol) was tre&ted with ~cetic ~nhydride (125 g, 1.22 mol) ~nd pyridine (97.3 g, 1.24 mol~ 8~ for Al in 5 Ex~mpl~ 2. The product w~ disti.lled ln vacuo to providle 126 g (86%~ of A6 ~ lightly yellow oil, bp 160-16~C (0.15 mm).
lH NMR (300 MHz, CDC13) ~ 2.07 (~, 6H~ 3.65 (t, 4H~, 4.~8 (6, 4H), 6.80 ~m, 3H~, 7.27 ~t, 2H). 0 ~3~=r~ 4-~Di-(2-~cetoxyethyl~minolbenz~ldehyde _ (A7~
N,N Di-(2-scetoxyethyl)aniline ~A6~ ~126 g, 0.476 mol) was re~cted with pho~phorou~ oxychloride (B0.3 g, 0.524 mol) in DMF ~3 for A2 in Ex~mple 3.
15 The product w~ di~tilled at 155-175~C (0.15 mm) to yield 130 g (~3~) of A7 a~ An orsnge oil.
lH NMR (300 MHz, CDC13 ~ 2.Q0 (~, 6H~, 3.6,B
(t, 4H), 4.23 (t, 4H), 6.77 (d, 2H), 7.~8 (d, 2H), 9.70 (g, lH). 0 Exsm~B 4'-~Di-2-hydro~ thyl?amino-4-nitro stilbene ~A8 4-[Di-(2-acetoxyethyl)amino~ben2~1dehyde ~A7) (20.0 g, 0.682 mol w~ re~cted with 4.09 & ~0.102 mol) of 60% ~dium hydride dl~per~ion ~nd 20.5 g 25(0.075 mol) of 4-nitrobenzyldiethylphosphon~te (A4) for A3 in Example 5A The initial product was hydrolyzed ~5 before, producing dark red crystsl~ of A8 sfter recrystslliz~tion from 10% slcohol~c pyridine. Yield 13.7 g (61~). mp 181-3C.
lH NMR (300 MHz, (CD3~2S0~ S 3.45 (t, 4H), 3.54 ~t, 4H), 4.78 (t, 2H), 6.73 ~d, 2H), 7.06 ~d, lH), 7.38 (d, lH), 7.45 (d, 2H), 7.72 (d, 2H~, 8.15 (d, 2H). 13G{lH} NMR (75.5 MHz, tCD3)~SO) 53.~, 5~.~, 111.4 12~.6, 123.2, 124.0, 126~1, 128.6, 133.~, 145.0, 145.2 ~48.6.

~3~
-~5-Example 9 4 ' - (Di - 6 - scr~loyloxyhexyl)~mino-4-nitr~-~tilbene CA92 To ~ stirred ~olution of 4'-di-(6-hydroxy-hexyl)amino-4-nitro~tilbene (A53 (2.07 g, 4.61 mmol~, sdrY tri.ethylamlne (1.19 g, 11.7 mmol), 50 mL of dry diohlorometh~ne, and 30 mg of hydroquinvne ~t 0C
under nitrogen a~ sdded dropwi~e a ~oluion of 1.07 g (11.7 mmol~ of freshly distilled acryloyl chloride in 10 mL of dichloromethsne. The reaction mixture w~s lo~tirred for 1 hour ~t 0C and then for 16 hour~ st 25C. The ~olution w~s ~ashed twice with ~aturated ~odium bic~rbon~te ~50 mL) and twice with brine ~50 mL). After drying (MgS04) and remov~l of ~olvent at reduced pressure, a dark red oil w~
5deposited~ The product W~9 purifled by column chromfltography on sillc~ gel using dichloromethRne as eluent. Actu~l yield was impo~sible to meflsure because the prod~ct beg~n to polymerize spontaneously when all the ~olvent was removed.
~, 20 H NMR (300 MHz, CDC13) ~ 1.38 ~m, 8H~, 1.65 (m, ~H), 3.28 (t, 4H), 4.14 (t, 4H), 5.80 (dd, 2H~, 6.11 (m~ 2H), 6.38 (dd, ~H), 6.~6 (d, 2H), 6.87 (d, : lH~, 7.17 (d, lH)3 7.38 ~d, 2H), 7.57 (d, 2H), ~.13 ; (d, 2H~. 13C{lH~ NMR (75.5 MHz, CDC13) ~
~` 2S25.~, 2~.7, 27.~, 28.6, 50.g, 64.4, 111.~, 121.0, 122.3, 123.4, 124.1, 125.9, 128.6, ~33.~9 144.9, 145 7, 148.5, 1~.2.
; Exam~le 10 4'~(Di-6-meth~crvloYloxyhexyl)amino-4-~e~
4'-Di-(6 hydroxyhexyl~amino-4-nitrostilbene ~A5~ (2.43 g, 5.52 mmol) w~s reacted with freshly di~tilled methacryloyl chlorids and triethyl~mine under the ~me condition~ ~ in ~x~mple 9. The ~ product W8~ purifie~ ~y column chromatogrsphy on `~ 3s~ilic~ ~el using dichloromethane ~s eluentO A red oil : W8S obtained, but the yield could not be determined bec~u~e the compound tended to polymerize Ypont~neou~-~ 3~ ~7 ly when ~11 the ~olvent ~a~ removed.
H NMR (300 MHz, CDC13) ~ 1.39 (m9 8H), 1.68 (m, 8H~, 1.92 ~, 6H), 3.29 (t, 4H~, 4.13 (t, 4H), 5.53 (~, 2H), 6.~8 (~, 2H)J 6.60 ~d, 2Hj, 6.68 (d, s2H)~ 7.17 (d, lH), 7.38 (d, lH), 7.52 ~d, 2H~, 8.14 ~d, 2H). 13C{lH} NMR (75.5 MHz, CDC13) t 18.3, 25.9, ~6.8, 27.2, 28.6, 50.9, ~4.6, 111.6, 121.0, 123.4, 12~.1, 125.2, 1~6.0, 12~.6, 133 7 136.5, 145.1, 145.8, 148.6, 167.~. 0 Ex~mple 11 4'~ 2-methacryloyloxyethyl)~mino-4-nitro~tilben0 ~Atl~
4 t - Dl-(6-hydroxyhexyl~amino-4-nitrostilbene (A8~ ~2.43 g9 5.52 mmol) wa~ reacted with freshly di~tilled meth~cryloyl chloride Qnd ~riethylamine 15under the ~ame conditions a3 in Example 10. The product wa~ purifi2d by column chrom~togr~phy on ~ilic8 gel using dichloromethane a~ eluent. A red o~l WQ~ obt~ined which gradu~lly cry~talli~ed (mp 81-3C), but the yield could not be determined becsuse the 20 compound tended to polymeri~e spont~neou~ly when ~11 the ~olvent wa~ removed.
H NMR ~300 MHz, CDC13~ ~ 1.93 (~, 6H), 3.73 (t, 4H), 4.35 (t, 4H)9 5.58 5~, 2H), 6.09 (s, 2H~, 6.82 (d, 2H), 6.92 (d, lH~, 7.18 (d, lH), 7.44 (d, 252H), 7.56 (d, 2H), 8.16 ~d, 2H). C~ H~ NMR
~75.5 MHz, CDC13) & 18.3, 49.6, 61.6, 112.~, ~22.2, 124.1, 135.2, 125.~, 126.1, 128.6, 133.2, 14~.8, 146.~, 147.9, 167.~.
Example 12 4-MethYlmercaE~t_benzyl chloride (A12) To a stirred ~olution of 154 g (1 mol) of 4-methylmercaptobenzyl Alcohol in 1 liter of dry bensene W~3 ~dded dropwi~e 80 mL 1.1 mol~ of thionyl chlorlde. The mixture immediately turned blue. A~ter the addition of the thionyt chlor~de w~s compl0ted, 3sthe mixture W~9 he~ted ~t reflux for 2 hour~. After cooling the benzene ~nd exce~s thionyl chloride were di~tilled at ambient pre~3ure. The product WA5 3~

di~tilled in v~cuo ~t 105C (0.5 mm~, to yield 160 B
~93%) of ~ colorle~s liquld.
lNMR (300 MHz, CDC13, ~ 7,49 (~, 3H~, 4.57 (~, 2H)i 7.28 (dd, 4H).
5Ex~mPle~ 13 Diethxl 4-Meth~ercsptob_nzylpho~-Phon~te ~A13~
4-Methylmerc~ptobenzyl chloride (A12) (160 g, 0.94 mol~ WBS ~dded drop~i~e~ under nitrogen~ w~th : stirring to ~83 g ~1.1 mole) of triethylphospllite lowhich wa~ he~ted ~t reflux. When the addition of the 4-methylmercaptobenzyl chloride w~ completed, the mlxture was refluxed for sddition~l 4 hours~ The product wa~ di~tilled in vacuo to yield 229 g ~89%) of w~ter clear, vi~cous liquid bp 142 - 145C (0.025 mm).
lH NMR (300 MHz, CDC13), ~ 1~27 tt, 6H), 2.49 (~, 3H~, 3.13 (d, 2H), 4.04 (quintet~ 4H), 7.66 ~dd) 4H).
:: Exsmple 14 Dl~n~ eD~y~ ben R~n te (A14~
To ~ stirred solution of 174 g (0.6 mole) of diethyl 4-methylmerc~ptobenzylpho~ph~n~te ~A13) in 500 :~ mL of glaciel ~cetic ~cid w 5 added dropwi~e 171 g (1.5 mole~) of hydrogen peroxide ~30~ in wQter). The mixture w~ he~ted at reflux for 2 hour~. After 25cooling, the w~ter ~nd ~cetic acid were removed under reduced pre~ure snd the re~idue W8~ di~tilled to yield I21 g (66~ of very viscous liquid bp 21~-216C
~2 x 10 4 mm~.
H NMR ~300 MHz, CDC~3) ~ 3 (t, 6H), 3~ 3.01 (~, 3H)t 3.1g (d, 2H), 4.02 (quintett 4H3, 7.66 . ~dd~ 4H).
Ex~mple 15 4'-~Di-6-methaC~yloyloxyh~xylL~ -4 LL~ ene _~A~
4'-Di-(6-hydroxyhexyl)amino-4-methyl3ulfonyl-5~tilbene (10.0 g, 21.1 mmol) wa~ reacted with $reshlydistllled meth~cryloyl chloride ~nd triethylR~ine I under the ~sme conditions a~ in Ex~mple 10. The ~ .
,~

7~
,. .

product W9~ purified by oolumn chromsto~r~phy on ~ilic8 gel u~ing dichloromethane ~g eluent. A yellow oil was obtAined~ but the yield could not be determined because the compound tended to polymer~ze 5 spontHneou~ly ~hen ~11 the ~olvent wa~ removed.
H NMR ~300 MHz, CDC13 ~ 1.2:L (m, ~H~, 1.65 ~m, 8H), 1.98 ~s, 6H), 3.09 (~, 3H), 3.34 (t, 4H), 4.16 (t, 4H), 5.55 (s~ 2H), 6.10 (~, 2H), 6.62 ~d, 2H), 6.90 (d, lH), 7.09 (d, lH), 7.40 (d, 2H), 7~61 10 (d, 2H~, 7.89 (d, 2H).
Ex~mple 16 Poled film prePsred from 4'-Di-(6-scryloyloxyhexyl3~mino-4~nitrostilbene (A10) A composition w~ prep~red for spin cssting 15 of the following formulA:
0.63 gm A5 0.01 gm Photo~en~iti2er (81) 0.075 gm Activator (~2) 2 ml Dichlorometharle : 20where B2 wa~ methoxy-4-pyridinium tetr~fluoroborate and :~ Bl wa~
:;
: C~ ~CH3 o C ~ ~CH3 o_ :~ R R
R - phenyl.
U~ing ~ ~yrin~e the solution w~s placed between tr~nsp~rent indium tin oxide (IT0) electrode~
depo3ited on optic~l fl~t qusrtz ~ubstrste~ sep~r~ted by ~ 12 ~m poly(~thylene terephth~late3 ~pscer.
When the e~P between the electrodes w~ filled, a DC
volt~g2 u~ 1.75 X 105 V/cm w~ ~pplied ~cros~ the electrode~ to pole ~he moleculsr dipoles. The pole~
solution WR~ expos2d for 45 minutes with ~ 200 w~tt ' .

mercury v~por lamp to near UV rsdiation to create an vptlcal article containing sn optic~lly ~ctive tran~m~ion medium compri~ed of polar aligned molecular dipoles and a croaslinked polymeric sbinder. Upon remov&l of the externally ~pplied electrlc field, the Moleculsr dipoles rem~ined in po~ar alignment. The tr~nsmi~sion medium produced ~ppesred on ViSUAl inspection to be transparent and colorless.
0 X(2) W8S estimated to be in the r&n8e of from 5 X 10 9 to 1 X ~ a 8 esu~
Example 17 Poled film prePared from 4'-~Di-6-sulfonylst _bene (A15) A compo~ition was prepared for ~pin ca3ting of the following formula:
0.45 gm A15 0.010 gm Photosensitizer (Bl) 0.070 gm Activator (B2) 2 ml Dichloromethane where Bl an~ B2 are as defined in Example 16.
The solution was spln cast at 250 rpm onto 250 ~m gap side-by- ide chromium electrode~ on a clear plastic support by first thoroughly wetting the 259upport and electrode surfaces with the solution before ~pinning. An electric field of 8 X 104 V/cm ~: was plsced across the film snd held for 4 hours while crosslinking occurred 8S the re~ult of exposure to room light, ~ince the photosensitizer exhibited a 30 peak absorption at 532 nm.
The invention has been descrlbed in det~l ~ith particular reference to preferred embodimenta thereof, but it will be understood thst varlstions ~nd modlfication~ can be effected withln the spirit 35 ~nd scope of the invention.

Claims (20)

1. An optical article containing, for the transmission of electromagnetic radiation, a medium exhibiting a second order polarization susceptibility greater than 10-9 electrostatic units comprised of organic polar aligned noncentrosymmetric molecular dipoles having an electron donor moiety linked through a conjugated .pi. bonding system to an electron acceptor moiety to permit oscillation of the molecular dipole between a ground state exhibiting a first dipole moment and an excited state exhibiting a differing dipole moment, characterized in that the molecular dipoles form repeating units in a crosslinked polymeric matrix.

2. An optical article according to claim 1 further characterized in that means are provided for directing electromagnetic radiation to said transmission medium.

3. An optical article according to claim 1 further characterized in that biasing means are provided for placing in electric field across said transmission medium.

4. An optical article according to claim 3 further characterized in that said biasing means includes at least one transparent electrode in contact with said transmission medium.

5. An optical article according to claim 1 further characterized in that said transmission medium lies in contact with a linear waveguide for electromagnetic radiation.

6. An optical article according to claim 1 further characterized in that said molecular dipole repeating units form at least 50 percent of said transmission medium.

7. An optical article according to claim 6 further characterized in that said molecular dipole repeating units form at least 70 percent of said transmission medium.

8. An optical article according to claim 1 further characterized in that said molecular dipole repeating units are crosslinked by crosslinking moieties.

9. An optical article according to claim 1 further characterized in that said molecular dipole repeating units satisfy the formula:
where A is an electron acceptor moiety;
D is an electron donor moiety;
E is a conjugated .pi. bonding system;
? is an integer of from 1 to 4; and L is a crosslinking moiety.

10. An optical article according to claim 9 further characterized in that A is a cyano, nitro, or sulfonyl electron acceptor moiety.

11. An optical article according to claim 9 further characterized in that D is an amino moiety.

12. An optical article according to claim 11 further characterized in that D is a secondary or tertiary amino moiety.

13. An optical article according to claim 9 further characterized in that A and E together form a sulfonimino moiety.

14. An optical article according to claim 9 further characterized in that D and E together form a pyridinium moiety.

15. An optical article according to claim 9 further characterized in that L is a crosslinking moiety of the formula where Ac is an activating moiety and R5 is hydrogen or a lower alkyl group of from 1 to 6 carbon atoms.

16. An optical Article according to claim 9 further characterized in that said molecular dipole repeating units satisfy one or combination of the formulae:
(a) (B) (c) (d) (e) (e) (f) (g) (h) (i) (j) (k) where A is an electron acceptor moiety;
D is an electron donor moiety;
E is a conjugated .pi. bonding system;
L is a crosslinking moiety;
Ra, Rd, R1, R2, and R4 are optionally substituted hydrocarbon spacer moieties containing from 2 to 10 carbon atoms; and R3 is hydrogen, an optionally substituted hydrocarbon moiety which, when substituted by said crosslinking moiety is L, is a spacer moiety containing from 2 to 10 carbon atoms.

17. An optical article according to claim 16 further characterized in that E is chosen to provide a 4,4'-stilbenoid conjugated .pi. bonding system.

18. An optical article according to claim 17 further characterized in that E is chosen to provide a 4,4'-stilbene conjugated .pi. bonding system.

19. An optical article according to claim 9 Further characterized in that said molecular dipole repeating units are comprised of one or a combination of repeating units satisfying the formulae:

(a) (b) (c) where A is an electron acceptor moiety;
D is an electron donor moiety;

G is independently in each occurrence a methine or aza moiety, with the proviso that no more than two aza moieties are next adjacent;
? is 2 or 3;
L is a crosslinking moiety;
n is an integer of from 1 to 3;
p is 0 or 1;
q is an integer of from 0 to 3, Ra is chosen from the group consisting of hydrogen and substituents which collectively, together with A, -SO2R1, or =NSO2R1, enhance the electron acceptance of the aromatic ring to which they are attached; and Rd is chosen from the group consisting of hydrogen and substituents which collectively, together with D, R2R3N-, or -R2, enhance the electron donation of the aromatic ring to which they are attached.

20. An optical article according to claim 19 further characterized that Ra and Rd are hydrogen in each occurrence, L is linked to at least one of oxygen, sulfur, and nitrogen atoms of the electron acceptor and donor moieties through an alkylene spacer containing from 2 to 10 carbon atoms, and L is present in the form of crosslinking groups of the formula:
where R5 is hydrogen or methyl.