Effects of Electron Beam Irradiation on Impact Value of Borosilicate Glass

Abstract

The effects of homogeneous irradiation of electron-beam (EB) with low voltage on the Charpy impact value (a_uc) of borosilicate glass were studied. When it performed in short bursts to maintain a low temperature, EB irradiation at a dosage from 0.04 to 0.22 MGy increased the a_uc value and enhanced its reproducibly. Based on the electron spin resonance (ESR) spectra, EB-irradiation formed apparent dangling bonds constructed with sodium atoms with high density of outer-shell electrons and terminated oxygen atoms of silica network in the borosilicate glass. When the intermolecular repulsive force generated the partial relaxation against residual and deformed strain, as well as expansion in front of crack tips near the sodium atoms, the initial a_uc enhancement of the borosilicate glass by the irradiation can be explained. Furthermore, the strong resistance to radiation damage of borosilicate glass was qualitatively confirmed. Although the large start point of irradiation dose to decrease the a_s value was 0.08 MGy for silica glass, it was 0.22 MGy for borosilicate glass. Consequently, the boron addition enhanced the resistivity to irradiation damage.