New type of intrinsic color centers in sodium silicate glasses

A series of glasses were studied of the composition (mass%): 22Na2O, 3CaO, 75SiO2 with a variable concentration of iron from 5 x 10/sup /minus/2/ to 3.5 x 10/sup /minus/2/ mass%. The color centers in the glasses were formed as a result of the action of UV or γ-radiation at room temperature. In the absorption spectra arising in sodium silicate glasses under the action of ionizing radiation, an absorption band with a maximum at 2.4 eV is observed. This band belongs to intrinsic hole color centers of a new type. The determination of its spectroscopic parameters has made it possible significantly to refine the parameters of the previously known bands with maxima in the region of 2.0 and 2.8 eV. The position of the maxima of the bands forming the absorption spectrum of the color centers in the region of 2-3 eV and their halfwidths are 2.0, 2.4, 2.85 and 0.49, 0.45, 0.7, respectively. The error in the description of the absorption spectra of color centers with the given parameters in the region of 2-3 eV by Gaussian contours does not exceed the measurement error of about 1%