ANALYSIS OF 2-DIMENSIONAL ENERGY AND RELAXATION-TIME DISTRIBUTIONS FROM TEMPERATURE-DEPENDENT BROAD-BAND DIELECTRIC-SPECTROSCOPY

We present a method to determine the two-dimensional 2D distribution G (W,ln tau(o)) of the relaxation time tau=tau(o)exp(W/k(B)T) using an i nversion of temperature-dependent broadband dielectric data. In contra st to the usual evaluation of 1D distributions g(tau), the 2D analysis reveals whether the broadening of a relaxation peak has its physical origins in a variation of the activation energy W, or the preexponenti al factor tau(o), or both. A study of the beta relaxation of a polymer blend demonstrates the validity of the analysis. We compare the distr ibution obtained from dielectric ac data (5 Hz-300 MHz, 100 K-300 K) w ith the results of a thermally stimulated depolarization currents samp ling technique. The contour line of G(W,ln tau(o)) is shown to follow the compensation law. [S0163-1829(98)05815-9].