Ion-implantation-induced stress in glasses: Variation of damage mode efficiency with changes in glass structure

Ion implantation induces lateral stress in glass due to the volume dilatation in the implanted near-surface region. Cantilever-beam experiments allow these quantities to be measured as a function of fluence. For fused silica the stress data for various incident ions are found to scale with atomic collision energy deposition. In sharp contrast, Pyrex (alkali-borosilicate) glass, (1-χ)(Na, K)2O x χB2O3x3SiO2 glass, and a sodalime (microscope slide) glass, yield stress values which scale with energy deposition into electronic processes. More significantly, this mode of damage production is dominant for the nuclear waste glasses PNL 76-68 and SRP. The void space in fused silica allows room for displaced Si and/or O. For the complex alkali-containing silicates, the interstitial volume is restricted. In the latter case, the probability increases that permanent defects can be formed by ionization-induced bond-breaking and network relaxation. These data imply that alpha-particle ionization energy deposition may be an important factor in nuclear waste glass radiation damage production, but the magnitude of this contribution has not yet been evaluated. (orig.)