Influence of Gas-Thermal Nitridation of Optical Lead Silicate Glass on Its Surface Properties

Optical lead silicate glass is subjected to the heat treatment in gaseous nitrogen (at excess pressure) at temperatures close to the softening temperature with the aim of improving the service properties of the surface. The distribution of elements in the surface layer of the nitrided glass is investigated by Auger spectroscopy. It is found that nitrogen occurs in the surface glass layer to a depth of 100 μm. In the glass subjected to the gas-thermal treatment, the service properties of the surface, such as the chemical durability, hydrophoby, and microhardness, are improved.