Two kinds of crosslinked polymers, containing 4-(4’-nitrophenylazo) aniline chromophore groups, were synthesized. Crosslinked polyacrylate was synthesized by polymerization of Dispersed Red-19 (DR-19) diacrylate, whereas crosslinked polyurethane was obtained by the reaction between (beta-hydroxy propyl acrylate-DR-1 methacrylate) copolymer and phenol-capped isocyanate-terminated DR-19. The crosslinked polymers were characterized by infra-red spectra, gel content and differential scanning calorimetry. The crosslinked polyacrylate and the crosslinked polyurethane exhibit glass transition temperatures at 125 and 160 degrees C, respectively. Thin, transparent, poled films of both crosslinked polymers were prepared by spin-coating, followed by thermal curing and corona poling at 160 degrees C for 1 h. The second-order non-linear optical properties of the poled films were studied by visible light absorbance measurement according to a one-dimensional, rigid oriented gas model. Long-term stability of the dipole alignment at 140 degrees C was demonstrated for the crosslinked polyurethane.