Electro-optical and dielectric characterizations of the Goldstone mode relaxation in ferroelectric chiral smectic C liquid crystals.

We report structural (helical pitch), electro-optical (tilt angle and spontaneous polarization) and dielectric (Goldstone mode) investigations of ferroelectric liquid crystals (FLCs) exhibiting the chiral smectic C phase (SmC()). All these characterizations were performed on two pure FLCs showing the SmC()-SmA-N() phase sequence and having small pitch, high spontaneous polarization and a large relaxation frequency. We have determined the Goldstone rotational viscosity and the twist elastic constant in the SmC() phase from the helical pitch, tilt angle, polarization, dielectric strength experimental data and from the relaxation frequency of the Goldstone-mode relaxation. An Arrhenius-type behaviour of the Goldstone rotational viscosity was obtained and the corresponding activation energies were evaluated.