Synthesis of stilbene-based azo dyes and application for dichroic materials in poly(vinyl alcohol) polarizing films

Stilbene-based azo dyes were synthesized and poly(vinyl alcohol) polarizing films were prepared using these dyes. Spectral properties of synthesized dyes were affected by amino group and intramolecular hydrogen bond in the coupling component ring. Adsorption of dye molecules onto the film was mainly influenced by hydrogen bonding interaction. Sodium sulfate added in the dyeing solution reduced the repulsion between dye anions and the film resulting in high degree of polarization. The increase in draw ratio improved the optical properties of the polarizing films.