Photoinduced changes in a liquid crystal (LC) alignment were measured for 4-octyloxy-4′-cyanobiphenyl containing quinizarin. Kinetic analyses were carried out for both photoinduced response and thermal relaxation of the LC alignment in the temperature range from 50°C to 78°C. Thermal relaxation curves of birefringence after termination of Ar+ laser irradiation show only one component in the smectic A phase, and two components in the nematic phase, revealing the microscopic environment of dye molecules in LC solvents. This change does not exactly correspond to the macroscopic phase transition from smectic to nematic, which suggests interaction between LC mesogens and dye molecules due to photoexcitation. An unrecoverable portion of birefringence for thermal ordering/relaxation processes after termination of photoirradiation was observed in the smectic phase measured in the course of heating process.