Optical and electrooptical properties of combined mesogenic polymers in dilute solutions and the mesophase

Optical, electrooptical, and dielectric properties of two combined polymers were compared in dilute solutions and the mesophase, using the measurements of flow birefringence, electrical birefringence, and orientational elastic deformations in electric field. It was found that the two polymers possess similar optical characteristics both in dilute solutions and in the nematic phase. The now birefringence in solutions was found to involve large-scale motion of the macromolecules. However, for both polymers, the Kerr constants are positive and differ by two orders of magnitude. This fact may be related to the deformational reorientation of the macromolecules in electric fields and the specific features of their dipolar architecture. In the nematic phase, dielectric anisotropies of both polymers differ both in the magnitude and the sign, although in solutions, the signs of the Kerr constants for these polymers are the same. This fact is interpreted in terms of the modem theories of nematic state.