Color-Center Kinetics in Cerium-Containing Glass

The formation and thermal bleaching of radiation-produced color centers in cerium-containing soda-silica glass are studied to determine the effect of cerium on color-center kinetics. The optical absorption changes occurring during and after irradiation with gamma and x rays are measured. The data are fit by equations obtained by integrating a set of reaction-rate equations. These equations are an approximate description of the following three processes that account qualitatively for the effects of cerium concentration and oxidation state: Ce(3+) ions, by capturing radiation-produced holes to form Ce(3+) (+) centers, inhibit formation of all other kinds of centers due to trapped holes; Ce(4+) ions, by capturing electrons to form (Ce(4+) + electron) centers, inhibit formation of all other kinds of centers due to trapped electrons and inhibit recombination of electrons with trapped holes; after cessation of irradiation, holes are transferred from their traps to Ce(3+) ions.