Sapphire and lithium fluoride have been used as windows in shock wave experiments to transmit reflected light from lasers to perform velocity measurements and to measure thermal radiation for temperature measurements, while maintaining substantial pressure at the interface. In the latter case there is a fundamental problem in that the radiation coming through the window is not that of the shocked sample but is the radiation from the interface, which in the ideal case is at some temperature between the temperature of the sample and the relatively cold windows. The interface temperature can be used to calculate the temperature of the sample, but values for the thermal diffusivities of both the window and the sample must be used in the heat flow calculation. Experiments are described that may resolve that difficulty. Two other problems thought to exist in these measurements are due to interface imperfections, such as gaps and the transparency of the windows under shock loading. Preliminary experiments are reported, which showed that in the pressure regime studied, the sapphire remained transparent. These experiments also showed that imperfections at the interface are a major problem, but it is a recognizable one and can be minimized or eliminated so that meaningful temperature measurements can be made. ¿ American Geophysical Union 1990