DYNAMIC LIGHT-SCATTERING NEAR THE SMECTIC-A SMECTIC-C-ASTERISK PHASE-TRANSITION IN THIN PLANAR CELLS

Using the quasielastic light scattering we have studied the order para meter dynamics close to the SmA-SmC phase transition in thin cells of ferroelectric liquid crystals, with planar boundary conditions. As a result of confinement, the bulk soft mode splits into two modes, where as from the thickness dependence of the relaxation rate of the phase m ode we measure the diffusion coefficients. The appearance of the chevr on structure is manifested in the temperature dependence of the relaxa tion rate of the phase mode.