Nonlinear optical polymers with novel benzoxazole chromophores: IV. Synthesis of maleimide–styrene and maleimide–methacrylate copolymers

Four nonlinear optical maleimide copolymers were synthesized by radical copolymerization of N-phenylmaleimide and methacrylate-based or styrene-based monomer with benzoxazole chromophores, respectively. The copolymers had high glass transition temperatures of 158°C and exhibited good thermal stability. The most transparent film was prepared from a alternating copolymer (PMIBz 2) derived from N-phenylmaleimide and styrene-based NLO monomer. The second harmonic generation coefficient and electro-optical coefficient ( r 33) of a poled PMIBz 2 film was 45 pm/V (at 1.064 μm) and 6.1 pm/V (at 1.3 μm), respectively. The temporal stability of r 33 of PMIBz 2 was superior to that of only methacrylate-based copolymer.