On the existence of two ferrielectric phases in antiferroelectric liquid crystals

Abstract

Abstract The optical rotatory power (ORP) has been measured as a function of the temperature for the antiferroelectric liquid crystal tolan C10 and C8, which respectively show in DSC measurements one and two ferrielectric phases. At the transition from the ferroelectric phase to the antiferroelectric one, it has been observed a change in the sign of the ORP for three different wavelenghts. These observations occur inside the ferrielectric phases, where the variations of the ORP as a function of the temperature are discussed as the consequence of the existence of different isostructural helicoidal ferrielectric phases.