DYNAMICAL STUDY OF HEAT-CONDUCTION IN LIQUID-CRYSTALS BY HIGH-SPEED OPTICAL HOLOGRAPHY

High-speed optical holography was applied to study the mesophase-isotropic phase transition of liquid crystals. A small thermal disturbance was generated by a CW laser beam at a point in the crystal and the changes of the refractive index in space and time were followed by using double-exposure optical holography with pulsed laser light. Thermal diffusivity was measured by changing the sample temperature in the isotropic phase. Anomalous behavior of thermal conduction was observed near the transition point. The results were analyzed by using hydrodynamic equations.