SYNTHESIS AND PROPERTIES OF 2 KINDS OF NONLINEAR-OPTICAL INTERPENETRATING POLYMER NETWORKS

Two kinds of interpenetrating polymer networks (IPNs) containing 4-(4' -nitrophenylazo)aniline chromophore groups were synthesized. A polyacr ylate network was prepared by polymerization of Dispersed Red-19 (DR-1 9) diacrylate, whereas an epoxy resin network was formed by reaction o f Bisphenol A-type epoxy resin E44 with 4(4'-nitrophenylazo)-3-amino a niline. A polyurethane network was synthesized by reaction between (be ta-hydroxyl propyl acrylate-DR-1 methacrylate) copolymer and phenol-ca pped isocynate-terminated DR-19. IPNs based on polyacrylate/epoxy resi n and IPNs based on polyurethane/epoxy resin were obtained by carrying out two corresponding kinds of reactions simultaneously. Both kinds o f IPNs were characterized by gel content, IR spectra, and DSC. The fir st kind of IPNs exhibits two glass transition temperatures at 122 and 165 degrees C, while the second kind of IPNs showed one broad glass tr ansition temperature at 172 degrees C. Thin and transparent poled film s of both IPNs were prepared by spin-coating, followed by thermal curi ng and corona poling at 160 degrees C for 1 h. The second-order nonlin ear optical properties of the poled films were studied by a visible li ght absorbance measurement according to the one-dimensional rigid orie nted gas model. The polyurethane/epoxy resin IPNs were more stable in dipole alignment than were the polyacrylate/epoxy resin IPNs at temper ature higher than 120 degrees C. (C) 1996 John Wiley & Sons, Inc.