Relation between dichroism of photoalignment azo dyes and their orientation under light wave field

Abstract

To date, azo dyes are widely used for liquid crystal photoalignment in flat panel displays. The relation of dichroism of azo dyes with their orientation under intensive light wave field is considered. Values of a truecos2φ¯ parameter, which characterizes orientation order of both molecules and dimers, were obtained as well as energy of their orientation process. Number of cooperatively oriented dye molecules was estimated. The angles distribution functions for different dimers were derived. Dipole electrical transition moments directed on angles close to 90° to the direction of maximal polarizability of dimers were revealed.