Thermally induced spectral diffusion for photoautomerization systems in polymer matrices

Abstract
Thermally induced spectral diffusion of a spectral hole was investigated using photoautomerization systems in various polymers. The broadening rates were correlated with the packing densities of the matrix polymers calculated by Bondi in the form of a Doolittle-type equation. The result was interpreted as the result of redistribution of entropically oriented free volume. The origin of the two-level system in amorphous polymers was discussed. The free volume is thought to be the origin of the intrinsic two-level system.