SYNTHESIS AND CHARACTERIZATION OF POLYOXETANES CONTAINING 4-CYANOBIPHENYL-BASED SIDE-GROUPS FOR NONLINEAR-OPTICAL APPLICATIONS .1. CHEMICALMODIFICATION OF POLY[3,3-BIS(CHLOROMETHYL)OXETANE] WITH SODIUM 4-CYANO-4'-BIPHENYL OXIDE
B. Guichard et al., SYNTHESIS AND CHARACTERIZATION OF POLYOXETANES CONTAINING 4-CYANOBIPHENYL-BASED SIDE-GROUPS FOR NONLINEAR-OPTICAL APPLICATIONS .1. CHEMICALMODIFICATION OF POLY[3,3-BIS(CHLOROMETHYL)OXETANE] WITH SODIUM 4-CYANO-4'-BIPHENYL OXIDE, Macromolecular chemistry and physics, 197(7), 1996, pp. 2185-2199
Two copolyethers were prepared by chemical modification of poly[3,3-bi
s(chloromethyl)oxetane] with sodium 4-cyano-4'-biphenyl oxide, employi
ng the concept of having the cyanobiphenyl species serve concomitantly
as both the nonlinear optical chromophore and the mesogenic moiety in
the polymer. Their thermal behavior was established by means of DSC a
nd optical microscopy. Some preliminary Corona poling experiments were
performed, and the second harmonic generation coefficients d(31) and
d(33) were measured by Maker fringe analysis. The results showed that
liquid crystallinity enhances field-induced polar ordering. The ratio
d(33)/d(31) was found to be much larger than 3, in agreement with the
theoretical models for electric field poling of liquid crystalline pol
ymers where hyperpolarizable chromophores are attached as side groups
to a polymer backbone.