FRACTAL DYNAMICS IN POLYMERIC GLASSES

We have analyzed the hole dynamics on a fractal lattice, and have obtained a spectral dimension (d) for the state density. This is the only independent fractal dimension needed in the discussions of the self-similar connectivity of hole motions, and the fluctuation-dissipation relationship controlling the glass relaxation and stretched exponential. The glass relaxation is a result of the local configurational rearrangements of molecular segments that is described by the hole motion. In contrast to polymeric fractals of flexible chains in solution or melt, we find that d decreases as the system is changed from linear to cross-linked polymers.