Structural Relaxation Processes in Polymers and Glasses as Studied by High Resolution Optical Spectroscopy

Abstract

Optical spectroscopy of glasses can be subdivided into two classes of experiments. One class deals with the intrinsic optical properties of disordered and glassy solids. Experiments of this kind are prevalent in the field of amorphous semiconductors. The optical experiments are mainly directed towards investigating the optical properties of the band-to-band transitions and yield information on the density of states of the disordered materials. One observes that the band gap, which is well defined for crystalline substances, is washed out in the case of amorphous materials and, hence, there are states in energy regimes which are forbidden in the crystalline solid.