Synthesis and nonlinear optical properties of 1,3- and 1,4-disubstituted type of poly(phenyleneethynylene)s containing electron-donor and acceptor group

The third-order nonlinear optical properties of 1,3- and 1,4-disubstituted poly(phenyleneethynylene)s containing electron-donor and acceptor groups were investigated in terms of the local polarization effect. The electron-donor and acceptor groups being set apart in the benzene ring adjacent to the triple bond in 1,4-disubstituted poly(phenyleneethynylene)s was found to increase the χ(3) value, together with the shift of the maximum absorption to longer wavelengths, while no significant effect was observed in the χ(3) value for 1,3-disubstituted poly(phenyleneethynylene)s having both electron-donor and acceptor groups present in a benzene ring, in accordance with the fact that the maximum absorption remains at shorter wavelength.