Electro-optic effects of the optically isotropic state induced by the incorporative effects of a polymer network and the chirality of liquid crystal

The electro-optical properties of optically isotropic liquid-crystalline composites prepared by in-situ photo-polymerization of cross-linking monomers in the isotropic phase of chiral liquid crystals were investigated. The magnitude of the electric birefringence of the composites decreased as the chirality of the liquid crystal increased. The clear Kerr effect was observed for the composites with high chirality. A large Kerr constant, being relatively insensitive to temperature, was obtained for the composites even in a temperature range below the isotropic-chiral-nematic phase-transition temperature. The response time of the Kerr effect at room temperature was on the order of tens to hundreds of microseconds.