Abstract
From the measurement of the radio frequency conductivity of two opalescent binary mixtures (nitrobenzene+n. hexane and aniline+cyclohexane) at a frequency of 400 kc/sec and also at a higher temperature at which the solution becomes clear, the relaxation time and the corresponding radius of the rotating unit under the high frequency field has been calculated. The results do not indicate the formation of clusters of molecules as proposed by Krishnan to explain the depolarization of scattered light in the critical opalescent stage. From the ratio of relaxation time, when the mixture is opalescent and when it is not, it has been observed that there is a sharp rise of viscosity at the critical stage and the theory of Fixman has been utilized to calculate the value of internal friction. An alternative method has been suggested to calculate the value of the internal friction which agrees well with the value calculated from Fixman’s theory. It has therefore been concluded that as assumed by Fixman, there is an intense density fluctuation in the critical stage and return to normal density fluctuation through diffusion dissipates energy which appears as a sharp increase of viscosity.
