Stretched-exponential relaxation of birefringence in a critical binary mixture.

Abstract

Transient electric birefringence in near-critical binary mixtures is found to exhibit stretchedexponential relaxation of the form exp[( t / ~ ) ' ] , with x constant and r diverging as a power law in reduced temperature. A simple scaling theory of this phenomenon is proposed, relating x and the relaxation-time exponent to static and dynamic critical exponents, with values in good agreement with experiment. The results yield information about the distribution of fluctuations in the one-phase region of critical fluids and mixtures.