Laser Photochemistry and Hole Burning Spectroscopy in Polymers and Glasses: External Field Effects

Abstract

Photochemical hole burning is a spectroscopic method based on site-selection via laser irradiation. It can be shown, that it yields a 103 to 104-fold increase in resolution if one deals with amorphous materials such as solid polymers. For various doped polymers (polyethylene, polystyrene, poly(methyl methacrylate), and poly(vinyl butyral)) we have made experiments under low electric field and strain field conditions. These experiments yield both, matrix parameters such as compressibilities and molecular parameters such as molecular dipole moment changes and polarizability changes. We will document, that the amorphous nature of the matrix breaks the molecular symmetry of the dopant molecules and gives rise to internal electric dipole moments or internal fields, which are absent in a periodic crystalline structure.