Unification of azo-polymer systems by photo-Induced molecular movement

Abstract

We review our recent research in the field of photochromic polymeric structures for optical data storage and nonlinear optics. We unify some of the sub -Themes of azopolymer structures in the light of photo -induced movement of azobenzene molecules. In particular, we discuss photo- induced effects in supramolecular assemblies containing azobenzene molecules (e.g. Langmuir- Blodgett -Kuhn structures and ultrathin silane layers). Reorientation of azobenzenes in these structures will be compared to that observed in spin -cast films. Photoisomerization and photo- induced orientation of azobenzene molecules is also studied at the molecular level by means of azosilane molecules chemisorbed on Silicon Oxide substrates. We establish a correlation between polymer architecture and sub -glass transition temperature (Tg) light- induced molecular movement in high Tg nonlinear optical azo- polyimide polymers. We show that the isomerization reaction itself depends on the polymer molecular structure, and we present evidence of light- induced molecular movement 325 °C below Tg of a rigid NLO azopolyimide polymer containing no flexible connector or tether.