An experimental method capable of measuring the instantaneous surface temperatures of very small areas (e.g., 1.778 x 10⁻⁵ min diameter) was developed and used to investigate the frictional interface of a sliding system - a fixed polymer sphere loaded against a thin sapphire disk. Basically, the method involves measuring the infrared radiance (which can be converted to temperature mathematically) from the contact area with a highly advanced infrared microscope. Friction at the interface is also obtained simultaneously. In this research, the surface temperatures of four different polymers, namely high density polyethylene, polytetrafluoroethylene, polystyrene, and polymethylmethacrylate were investigated. Effects of load and sliding speed on the friction and wear behavior of the polymers were examined. Finally, the experimental results were compared with theoretical calculations, and reasons for the discrepancies were discussed. / M. S.