SYNTHESIS OF AND THE 2ND-HARMONIC GENERATION BY A 1,4-PHENYLENEVINYLENE)-CO-(1,4-PHENYLENEVINYLENE)]

A -1,4-phenylevinylene)-co-(1,4-phenyl-enevinylene)] [poly(MNEPV-co-PV )] containing 30 mol % of the styryl-substituted 1,4-phenylenevinylene units was prepared via an organic-soluble precursor polymer. The prec ursor polymer, nyl)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 o n a poling device and heated stepwise to 235 degrees C at a field stre ngth of 10(5) V/cm to thermolyze it to the final, poled polyconjugated poly(MNEPV-co-PV). The second harmonic generation of the poled film w as measured at room temperature in transmission with a Y-cut quartz pl ate as reference using a Nd:YAG laser beam of 1064 nm at an angle of 9 0 degrees to the film. The chi((2)) value thus obtained was 2.0 x 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 degrees C.