EFFECTS OF SYMMETRICAL AND ANTISYMMETRIC STRESS TENSORS ON N-DIELECTRIC AND ALPHA-DIELECTRIC RELAXATIONS

We present a generalized hydrodynamic model for dielectric relaxation to describe the effect of spatial inhomogeneities in the polarization fluctuations in viscoelastic fluids. The model is a generalization of the simple Debye relaxation equation with the addition of the gradient of the total stress tensor. The two known modes of relaxation, N- and alpha-absorption can be incorporated in the model semiquantitatively, since we do not know the actual parameters involved. The comparison b etween our results and the experimental response reported for the N- a nd alpha-modes in polymers, shows that the predicted intensities of th e loss peaks are well represented. However, at lower and higher freque ncies the predicted curves deviate from the experimental ones. (C) 199 8 Elsevier Science B.V. All rights reserved.