Liquid crystal photoalignment on azo-dye layers

Effective photoalignment of liquid crystals (LCs) on spin-coated layers of azo dyes on the surface of ITO was observed. Methyl Red films were irradiat ed with linearly polarized light from an Ar+- laser. The layers align the e asy orientation axis of LC 5CB perpendicular to the polarization of the inc ident light. photo-induced cis/trans isomerization and changes of the inter action between dye molecules and the surface of the ITO are the proposed me chanism of photoalignment. Photoalignment of 5CB on layers of sulfasalazine after exposure to polarized UV light was also explored. A thermal induced anchoring transition was observed in addition to features similar to those of methyl red.