Single crystals of PbWO4 have been studied in connection with their ap
plication for high energy physics experiments. A comprehensive charact
erization of PbWO4, by means of transmission, thermoluminescence and e
mission spectra measurements will be described. Annealing procedures i
n the air and vacuum atmospheres at high temperatures were used to stu
dy induced changes in the transmission. The gamma radiation induced ch
anges in the absorption spectra of several PbWO4 crystals of different
origin, and intentionally doped will be illustrated.