Ultrasonic investigation of rotational isomerism on mesomorphic compounds

Abstract

The attenuation coefficient of ultrasonic longitudinal waves in the nematic phase of the p methoxy p' n butyl azoxybenzene (Licristal Merck IV) has been measured as a function of both frequency and temperature. For temperatures far below the nematic-isotropic transition, the frequency dependence of the attenuation can be accounted for by a single relaxational process. The temperature dependence of the relaxational frequency appears to support the assumption of rotational isomerism in the flexible ends of the molecules