Nonequilibrium phase behaviour of a chiral side chain polymer

The phase behaviour of an LC polysiloxane is found to depend on the previou s history of the sample. Fast cooling from the isotropic state results in t he formation of a nonequilibrium, highly transparent, and poorly birefringe nt layered mesophase, (an amorphous TGB-like smectic structure has been sug gested). In contrast, thin samples annealed by several heating/cooling cycl es or in an electric field form conventional smectic phases of the A* and C * types. The pyroelectric effect, optical switching and soft mode of these phases have been studied. (C) 1998 Elsevier Science Ltd. All rights reserve d.