SOL-GEL COATINGS ON FLOAT GLASS

摘要

The refractive coefficients and thickness of two-sided sol-gel coatings of different compositions deposited on float glass by the immersion method are measured. It is established that the refractive coefficient on the top surface of a sample, which contacts the protective atmosphere of the melt tank during glass working, is higher and the film thickness is smaller than those on the bottom surface. This is due to the different properties of the opposite surfaces of thermally polished glass, which is related to the different tin concentrations in the surface layers. The traditional method for producing glass with a set of required service properties is based on correcting the glass composition by introducing additional components. This requires substantial expenses and drastic changes in machinery and production technology. A cheaper and more advanced way is modifying the surface glass layer by applying thin coatings. This method has long been used extensively in the production of optical instruments for the purpose of "clarifying" (increasing the transmission coefficient) of glass parts. For this purpose a silicon dioxide film is deposited on glass surface, since its refractive index is lower than that of the glass part material.