Nonlinear optical polymers with novel benzoxazole chromophores III. Synthesis and characterization of self-crosslinkable glycidyl methacrylate copolymers

Abstract

Self-crosslinkable nonlinear optical copolymers (PGBz) were synthesized by radical copolymerization of vinyl monomer containing benzoxazole chromophore and glycidyl methacrylate as a comonomer. The thermal properties of these copolymers were compared to the corresponding copolymers (PGSt) containing stilbene chromophores. It was found that both the PGBz and PGSt copolymers were amorphous and fairly soluble in chlorinated solvents such as trichloroethane and tetrachloroethane. The glass transition temperatures of the copolymers were in the range of 117-134 degrees C depending on the contents of benzoxazole chromophores. From the results of thermogravimetric analysis before and after heat treatment, the thermal stability of PGBz copolymers was improved after heat treatment due to crosslinked polymer networks. The crosslinked PGBz had a better thermal stability than crosslinked PGSt. The nonlinear optical coefficient (d(33)) and electro-optical coefficient (r(33)) of PGBz was 63.4 pm/V (at 1064 nm) and 7.8 pm/V (1.3 mu m), respectively. (C) 1999 Elsevier Science B.V. All rights reserved.