A NEW CLASS OF 2ND-ORDER NONLINEAR-OPTICAL MATERIAL - STILBAZOLIUM BENZIMIDAZOLATE COVALENTLY BOUND TO POLYMER BACKBONE

This paper describes the first example of the preparation of stilbazol ium benzimidazolate covalently bound to polymer backbone using a novel methacrylate monomer, -{4-[2-(4-methacryloyloxyphenyl)ethenyl]pyridin io} benzimidazolate. A free radical copolymerization of cryloyloxyphen yl)ethenyl]pyridinio}benzimidazolate (1 equiv.) with butyl methacrylat e (6 equiv.) provided a methacrylate polymer containing 1.7 mol% of be taine units. The resulting polymer exhibited a glass transition temper ature of 30 degrees C. The number-average (M-n) and weight-average (M- w) molecular masses were 36 900 and 79 300, respectively, estimated by GPC measurement. The second-order non-linear optical property of the obtained polymer was investigated by second-harmonic generation (SHG) measurements applying the Maker fringe method using a Q-switched Nd:YA G laser (1064 nm) as an exciting beam after corona-poling, indicating that the d(33) value of the resulting copolymer was 5.1 pm V-1.