Nonlinear Optical Polymers with Novel Benzoxazole Chromophores. 1. PMMA Copolymers with Good Thermal and Temporal Stability

Abstract

New copolymers (PMBz) from the benzoxazole-based vinyl monomer and methylmethacrylate as a comonomer, were synthesized for an improvement of thermal stability of second-order nonlinear optical activity. The thermal stability of the chromophores in PMBz copolymers monitored by IR and UV-visible spectroscopy was much better than in PMSt copolymer bearing general pendant stilbene units. The electro-optic coefficient r₃₃ of the poled PMBz film exhibited as large as 45 pm/V at 632 nm of He-Ne laser. Thermal relaxation behavior of the poled PMBz films at 100[ddot]C showed that the PMBz having more rigid benzoxazole structure had better temporal stability of r₃₃ compared to the general stilbene structure.