Helix dynamics and electro-optic switching in ferroelectric smectic C liquid crystals

The responses of symmetric square and triangular wave pulses have been inve stigated in planar cells of two ferroelectric liquid crystalline mixtures F LC-6430 and SCE-13 in the SmC* phase. The samples were sandwiched between t wo parallel polyimide coated substrates. The cells containing SCE-13 and FL C-6430 were considered in the surface stabilised state (p>d) and volume sta bilised state (pcd) respectively, (p is the helix pitch and d is the sample thickness). Dynamic processes associated with the helix unwinding and wind ing by applying bias -10V - 0V- + 10V has been studied. The spontaneous pol arisation (P-s), response time (tau(R)) and torsional viscosity (eta) have been evaluated in these materials. Materials in surface stabilised configur ation show surface switching while in DHF configuration switching is due to bulk and surface effects.