Polymethacrylate copolymers containing 4,5-dicyanoimidazole-based chromophores and their nonlinear optical behavior

Summary: Two series of methacrylate copolymers were prepared, based on two new nonlinear optically (NLO) active chromophores 2-[4-(N-methacryloyloxyethyl-N-methylamino) phenylazo]-4,5-dicyanoimidazole (chromophore A) and 1-ethyl-2-[4-(N-methacryloyloxyethyl-N-methylamino)phenylazo]- 4,5-dicyanoimidazole (chromophore B). Second order NLO properties of the two series of copolymers (A or B as monomer and methyl methacrylate as the comonomer) were investigated by SHG procedures at the fundamental wavelength 1368 nm; d33 values in the range 0.2–3.3 pm/V were obtained, depending on the chromophore and on its molar content. The dependence of d33 on the molar content of chromophore was investigated in the two cases.