1A15 REENTRANT SMECTIC PHASES SHOWING LARGE ELECTROCLINIC EFFECT IN A DICHIRAL LIQUID CRYSTAL

Abstract

A ferroelectric phase and a reentrant ferroelectric phase of a dichiral liquid crystal were studied by means of electro-optical switching, spontaneous polarization, X-ray, circular dichroism and dielectric measurements. Both phases showed V-shaped switching. Four models, de Vries type SmA, deformed helix, V-shaped switching due to polarization charge and modulated SmC* models, were examined for the model of the V-shaped switching. Among the models, de Vries type SmA model was denied by circular dichroism measurement. Small birefringence dependence upon application of an electric field contradicted the deformed helix model. The validity of the remaining two models with some modification are discussed considering other experimental results.