Photoinduced dichroism in various polymers containing the same azo dye has been studied. "Angular hole burning" and molecular reorientation have been identified by analysis of dichroism dynamics at various probe wavelengths. The glass-transition temperature Tg is of major relevance for the reorientation of optically active molecules. For low Tg (below ambient temperature) thermal diffusion impedes anisotropy buildup. For higher Tg the angular distribution induced by the polarized pump beam is frozen. We propose a simple model based on diffusion rates in trans and cis molecules.
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics