Influence of point defects in a surface layer on the strength characteristics of glasses

The influence of the nature and the concentration of defects in a surface layer on the radiation resistance and the microhardness of silicate glasses is studied by photoemission spectroscopy. The investigation is performed with two types of silicate glasses: the K8 optical glass irradiated with fast electrons and an industrial sheet glass with a thermally polished surface. It is established that the radiation resistance and microhardness of glasses are determined by the content of structural defects of a particular nature. The radiation resistance of the surface of K8 optical glass decreases with an increase in the concentration of radiation E-4(-)-centers, which are representative of the density of band-tail localized electron states recharged by irradiation. The microhardness of the studied glasses with different treatment of their surface depends linearly on the number of defect centers at the nonbridging and radiation-damaged bridging bonds of the silicon-oxygen network.