DIELECTRIC, OPTICAL AND TSM MEASUREMENTS ON SEMI-PERFLUORO FERRO-ELECTRIC AND ANTIFERRO-ELECTRIC LIQUID-CRYSTALS

Two compounds with very similar chemical formulae but different phase sequences, denoted by F3H6 and P4H6, have been studied by dielectric, optical and TSM measurements, and by optical and polarization hysteres is loops. The light diffraction technique was used to measure the heli cal pitch (p), which was found to be nearly temperature independent. S ix relaxation modes have been identified. The polarization and tilt an gle results are discussed using a simple phenomenological model and fi tted to the equation P-0/theta(0) approximate to (1/epsilon epsilon(0) C - Omega/C theta(0)(2))(-1).The parameters C and Omega were determine d from the fitting.