THERMOLUMINESCENCE EMISSION-SPECTRA AND OPTICAL BLEACHING OF OLIGOCLASE

Thermoluminescence (TL) spectra of oligoclase samples have been record ed in the temperature range from 300 to 700 K and the wavelength range from 300 to 850 nm. Like other feldspars, oligoclase produces blue (p eaking at 460 nm) and red (peaking at 765 nm) emission bands. The maxi mum of the red emission occurs 20 K lower than that of the blue band. Optical bleaching was performed at wavelengths varying from 360 to 800 nm. Bleaching of artificially irradiated oligoclase causes a decrease of the TL signal. The bleaching efficiency increases with decreasing wavelength. Bleaching does not only influence the height of the glow c urve but also the shape. An interesting observation is that the ratio of the blue and red band intensities is not affected by a bleaching pr ocedure. No evidence has been found that bleaching influences the shap e of the emission spectra. The correlation between the blue and red ba nds is discussed.