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ethers), poly(amino ethers), or epoxy thermosets. We will describe the synthesis and NLO properties of these novel functional chromophores, and of the polymers based on these chromophores. H I R--(A)m (D)n-- R--C-- N- N-

RESULTS AND DISCUSSION General Preparation of Hydrazone Chromophores Polymerizable nonlinear optically active hydrazones were prepared in high yield by the acid-catalyzed condensation of substituted aryl hydrazines with hydroxy- or amino-functional ketones or aldehydes. The NLO active hydrazones are high melting solids that were generally recovered in 80-95% yields. In most cases, no extensive purification was required before polymerization. The preparation of compound 2 is shown as an example (Scheme 1). Scheme 1. Preparation of Polymerizable Hydrazone 2. NO2

NH

0N[Hf]

HO

OH

NH 2

HO

2

OH

Using this methodology, structural variations are readily introduced into the chromophore, and ultimately into the NLO-active polymers. Monomers have been prepared with nitro, dinitro, and tricyanovinyl electron withdrawing groups, in addition to hydroxyl or amino functionalities (Table I). With the exception of the tricyanovinyl-functional 4, hydrazones 2-7 have absorption maxima between 406 and 431 nm. Second-order hyperpolarizability (p43) measured for the compounds in solution by EFISH, shows significant resonance enhancement at 1064 nm, with values ranging from 2571 x 10-48 esu for 3, a bis-hydrazone, to 600 x 10 48 esu for 7, a hydrazone with both hydroxyl and amino functional groups. When measured at 1579 nm, the p43 values drop substantially, to 672 x 10-48 esu for 3, about one-half of that measured for DANS. Compound 4, with a strongly electron-withdrawing tricyanovinyl group, has a ,maxof 553 nm, and a p43 of 2440 x 10-48 esu when measured at 1579 nm. The amino-functional hydrazone 5, with amino groups located at the 4,4' positions, has a p43 of 1950 x 1048 esu, while p43 for 6 (substituted at the 3,3' positions) drops to 680 x 1048 esu. 54

No

Table I. Structures and Properties of Selected Polymerizable Hydrazones. Structure Yield (%) m.p. ('C) ,maxa ,03 10 64 b 04. 15 7 9b

.NH

2

1

90

245-247

415

827

455

191-193

418

2571

672

81

250-251

553

-

2440

H

86

219-221

n.a.

1226

n.a.

NNH

89

196-198

431

1950

400

91

202-205

406

680

-

OH

HN

HC N

INCH,

.NC.?94

3 HO

OH NC

C

N'

2

HOJýc

5

6

N

OH

H2NOH,

7

NNH H 2N -CJ

NH2

anrm bpp3 values measured in solution by EFISH at indicated wavelength (x 10-4 8esu).

4,4'-dimethylaminonitrostilbene (DANS): 11131064=2765 x 10-48 esu; 41131579=1271 x 10-4 8esu 55

Preparation of Hydrazone-Containing Polycarbonates Arylhydrazones with two hydroxyl groups were incorporated into polycarbonates by one of two methods (Scheme 2). In the first, a random copolycarbonate was generated by the reaction of a mixture of diphenols, one of which contained the hydrazone moiety, with phosgene in the presence of pyridine as a hydrohalide acceptor. Alternating copolycarbonates were prepared by the reaction of the bis-chloroformate of