Birefringence and Order of Liquid Crystal Polymer Solutions

ABSTRACTBirefringence measurements of nematic solutions of the poly(p-phenylene benzobisthiazole), PBT, using interference between the ordinary and extraordinary waves created when a plane polarized wave enters the crystal, are described. The measured birefringence is high, e.g., ne – no varies from 0.05 to 0.09 at 633 nm for polymer concentrations 4×10−2 < c < 10×10−2(g/cm3). These data are discussed with the implications they have on the order parameter in these solutions.