We study optical switching properties of novel azobenzene liquid crystal (azo LC) material systems based on mesogenic azo dyes distinguished by enhanced absorption in the visible spectrum and a short lifetime of the photoexcited state. Due to their mesogenic nature these azo dyes can be doped at high concentrations in room temperature LCs. This permits one to obtain results using low energy density values required for observation of strong nonlinear optical processes and short spontaneous restoration times of their original state. A photoinduced nematic-isotropic phase transition could be induced with a single nanosecond pulse. Thin material layers of the order of radiation wavelength were used in the study.© (2009) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.