UV ABSORPTION IN X-RAYED TRIGLYCINE SULFATE AND ITS TEMPERATURE DEPENDENCE.

The uv absorption induced in TGS by x-irradiation at room temperature does not appear when the irradiation takes place at 77 degree K. Subsequent annealing of the irradiated crystal at temperatures above 200 degree K causes the uv absorption to come up. As function of the annealing temperature the absorption grows in steps at 200, 300 and 370 degree K with activation energies of about 0. 3, 0. 5 and 0. 8 eV respectively. The absorption band itself is composed of three components at 255, 290 and 360 nm. The absorption bands can be bleached optically at 77 degree K. Selective bleaching of the various components can also be obtained by illumination with wavelengths within the given component. Warming of the bleached crystal causes the uv absorption to appear again. The results are discussed and a model is given to explain the observations.