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

Self-crosslinkable nonlinear optical copolymers (PGBz) were synthesized by radical copolymerization of vinyl monomer containing benzoxazole chromophor e 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 trichlor oethane and tetrachloroethane. The glass transition temperatures of the cop olymers were in the range of 117-134 degrees C depending on the contents of benzoxazole chromophores. From the results of thermogravimetric analysis b efore and after heat treatment, the thermal stability of PGBz copolymers wa s improved after heat treatment due to crosslinked polymer networks. The cr osslinked PGBz had a better thermal stability than crosslinked PGSt. The no nlinear 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.