A SIMPLE APPROACH TO THE DIELECTRIC-RELAXATION BEHAVIOR OF A LIQUID-CRYSTALLINE POLYMER AND ITS APPLICATION TO THE DETERMINATION OF THE DIRECTOR ORDER PARAMETER FOR PARTIALLY ALIGNED MATERIALS

A theory for the dielectric relaxation behavior of a partially aligned liquid crystalline (LC) material is described. It is shown, quite generally, that the complex dielectric permittivity may be expressed in terms of the parallel ( epsilon parallel ) and perpendicular ( epsilon // PERPEND ) components for the permittivity of the mesophase and S//d, the director order parameter, where epsilon // parallel and epsilon // PERPEND may themselves be expressed in terms of molecular quantities, including S the mesophase order parameter. The theory is applied to experimental data for a nematic siloxane LC side-chain polymer. The consistency of the derived values of S//d provides experimental confirmation of our approach.