Optical Responses of Azo Dye Doped Cholesteric Liquid Crystal-Polymer Composite System

Liquid crystals and polymers offer unique optical and electro-optical properties which make them ideal choice for opto-electronic and sensing devices. Doping absorbing dyes into liquid crystals increase their optical responses significantly due to increased absorption in the visible region, absorption induced intermolecular and other guest host effects. In the present paper we have studied the mixture consisting of cholesteric liquid crystal, a polymer and the azo dye. The investigation was performed by (a) Studying the texture and clearing temperature of pure cholesteric liquid crystal (CLC) using Polarizing microscope, (b) The study was repeated for a mixture of CLC and Polymer taken in different proportions, (c) The change in texture at various temperature and the effect on clearing temperature was obtained by doping the CLC with azobenzene dye, and (d) The change in texture and clearing temperature was further studied for the mixture consisting of CLC and Polymer doped with azo dye. The system was investigated further by studying the % transmission, using UV/VIS photo spectrometer, in the visible range for a pure CLC, a mixture of CLC and azo dye, a mixture of CP and MMA doped with azo dye.