ORIGIN OF DISPERSION IN DIPOLAR RELAXATIONS OF GLASSES

Dispersive relaxations typically found in glassy systems stem from a distribution of response times, spread either heterogeneously or homogeneously within the ensemble of sites. To distinguish between these two possibilities we follow the dynamics of dipole solvation, a technique which provides valuable insight on relaxation in both the liquid and the glassy regime. Employing the dynamic mean spherical approximation (MSA) theory, with epsilon(omega) as an input, we calculate the solvation time evolution in the homogeneous and heterogeneous limits. Due to the remarkable agreement between the homogeneous MSA and the observed solvation in 2-methyltetrahydrofuran at T(G) + 3 K = 94 K we conclude on the homogeneous nature of dispersion for dipolar relaxations.