Side chain second-order nonlinear optical (NLO) polymers were synthesized for studying the relaxation dynamics of the electro-optic effect. 2-(Methyl-14- [2-{4-nitrophenyl)-vinyl]-phenyl}-amino)-ethanol was synthesized to be bound to methacrylate repeating unit. We synthesized homopolymer and copolymer to compare the temporal relaxation behavior of second-order NLO properties. For this purpose, a real time poled and probe technique was employed to investigate the relationship between the measurement temperature and the electro-optic (E/O) property. The relaxation behavior of the E/O effect was analyzed below and above the glass transition temperature.