Synthesis of and the second-harmonic generation by a poly[(2-methoxy-5-{2-(4-nitrophenyl)ethenyl}-1,4-phenylenevinylene)-co-(1,4- phenylenevinylene)]

Abstract

Apoly[(2-methoxy-5-{2-(4-nitrophenyl)ethenyl}-1,4-phenylenevinylene)-co-(1, 4-phenyl-enev-inylene)] [poly(MNEPV-co-PV)] containing 30 mol % of the styryl-substituted 1,4-phenylenevinylene units was prepared via an organic-soluble precursor polymer. The precursor polymer, poly[{2-methoxy-5-(2-(4-nitrophenyl)ethenyl)-1,4-phenylene-1 -(benzyloxy)ethylene}-co-{1,4-phenylene-1-(benzyloxy)ethylene}], was cast into a thin film from its solution in 1,1,2,2-tetrachloroethane. The thin film was formed on a poling device and heated stepwise to 235°C at a field strength of 105 V/cm to thermolyze it to the final, poled polyconjugated poly(MNEPV-co-PV). The second harmonic generation of the poled film was measured at room temperature in transmission with a Y-cut quartz plate as reference using a Nd:YAG laser beam of 1064 nm at an angle of 90° to the film. The χ(2) value thus obtained was 2.0 × 10-8 esu and the value remained the same for more than a month even when the film was subjected to a thermal history up to 100°C. © 1995 American Chemical Society.