Glow curves and thermoluminescence spectra taken at various temperatures during the glow have been recorded simultaneously. Spectra were obtained with a rapid-scanning spectrophotometer using a liquid-air cooled photomultiplier in conjunction with a cathode-ray oscilloscope. Peaks of the same wavelength were found to be repeated several times in the temperature range of 80-600°K. Thermal pretreatment was found to enhance the various glow peaks by factors of a few thousands. On prolonged heat treatment the peaks above room temperature were found to decrease in intensity, while those at lower temperatures continue to grow even after 80 hours of heat treatment at 550°C. Essentially the same results were obtained for both natural (Dead Sea) crystals and artificial ones.