ELECTROOPTIC PROPERTIES OF CHIRAL SMECTIC LIQUID-CRYSTALS WITH A DIPOLAR ORDER

The compound 4-(1-methylheptyloxycarbonyl)phenol 4'-octyloxy biphenyl-4-carbonate exhibits ferroelectric S(C)*, paraelectric S(A), antiferroelectric S(CA)* and two ferrielectric S(Calpha)* and S(Cgamma)* phases. From the electrooptic response measured in the frequency range 100 Hz to 100 kHz the soft mode relaxation frequency in the paraelectric phase and the Goldstone mode relaxation frequency in the ferrielectric and ferroelectric phases have been determined. In the S(Cgamma)* phase the shape of the real and imaginary parts of the electrooptic frequency dispersion reflects dipolar disorder. In the ferrielectric, ferroelectric and antiferroelectric phases the temperature dependencies of both the spontaneous polarization and the tilt angle are measured under an electric field high enough to enforce the saturated ferroelectric state. The dependencies are smooth within the entire temperature range studied indicating all the studied phases are indistinguishable under high electric field.