Paramagnetic Resonance Spectra of Alkali Borate Glasses Irradiated with Gamma-Rays

Abstract

Borate glasses containing alkali oxides were irradiated with gamma rays at room temperature. The samples were pulverized and enclosed in a glass tube in vacuo. The total dose was approximates 5 x 106 r. The electron- spin resonance absorption of the irradiated glass was measured at 9000 Mc. The glass samples showed a prominent resonance absorption of g = 2.0, with minor differences in their structures. Fused borate and alkali borate glasses displayed a magnetic hyperfine structure of 4 peaks separated from each other by 13.5 gauss. The magnetic hyperfine structure may be ascribed to B/sup 11/ with I = 3/2. A defect model by which an electron is removed from an oxygen atom seems adequate to account for the observed magnetic hyperfine structure. The alkali borate glasses showed additional resonance absorption, which seems to originate from alkali metals. The presence of H2O or OH- ion in glass and water absorbed on the glass surface inhibited the formation of radioinduced defect centers. (H.H.D.)