Change of Polarizability of Molecules at the Isotropic Liquid – Nematic – Smectic A – Crystal B Phase Transitions of the Liquid Crystal 4O.8

Abstract
The temperature dependences of molecular polarizability parameters (longitudinal and transverse components, mean value and anisotropy) were determined in nematic, smectic A and crystalline B phases of 4- butyloxybenzylidene-4'-octylaniline (4O.8) liquid crystal. For the nematic phase, the earlier predicted nonlinear dependences of polarizability parameters on the orientational order parameter were revealed. The influence of the one-dimensional density-wave condensation at the nematic – smectic A phase transition and the quasi-twodimensional crystallization of weekly-connected smectic layers at the smectic A – crystal B phase transition on polarizability parameters was discovered. It was established that the changes of polarizability parameters within each phase of the studied liquid crystal are connected either with the change in the conformation of the aromatic molecular cores or with intermolecular interactions.

Keywords: polarizability of mesogenic molecules, phase transitions in liquid crystals, molecular conformation, intermolecular interactions