We report the characterization of copolymers of methyl methacrylate (MMA) and 2-propenoic acid, 2-methyl-, 2[[[[4-methyl-3-[[(2-methyl-4-nitrophenyl)amino] carbonyl]aminophenyl]carbonyl]oxy]ethyl ester (PAMEE) exhibiting nonlinear optical (NLO) properties. The linear copolymer, poly(MMA-co-PAMEE), with a NLO chromophore incorporated into PAMME exhibits a high glass transition temperature of 131 degrees C, as determined by DSC. The thin films of copolymers, which were cast on microscopic glass slides, were optically transparent, and the corona poled polymers produced relatively large and stable second harmonic generation (SHG) signals at room temperature. The nonlinear coefficient d(33) of the crosslinked copolymer containing 30 wt % PAMEE was 30.8 pm/V. The SHG signal strength remained unchanged, even after 120 days, and exhibited excellent thermal stability at. 65 degrees C.