Influence of environment on surface of the ancient glasses

Investigations have produced significant advances in understanding glass surfaces and their environmental corrosion. This process acts as a destructive factor, due to inter-reactions between the glass surface and the surrounding environment. The main point of this paper is to analyse glass corrosion processes, mainly using ancient model glasses in different surroundings. The experiments were made for glasses with composition of the chosen ancient glasses. The tests were carried out in H2O, 0.1 M HCl, 20% H2SO4, 10% NaOH, 5% NaCl (in salt spray chamber) and H2SO4 with pH = 4 (in salt spray chamber). The results of this induced process were later analysed by X-ray diffraction, infrared Fourier transform spectroscopy, scanning electron microscopy observation and chemical analyses. Infrared spectra indicate that corrosion is connected mainly with the action of water, organic compounds and carbonates on the surface layer. Alkali react 100 times stronger than other media, destroying the surface silica gel layer. Destruction of Si-O-Si bonding pays a predominant role in the reaction between alkali and glass. The thickness of this layer is proportional to the time of reaction. Surface changes show the layer morphology, depending on the character of attacking media. Changes in chemistry and structure of glass surface, due to corrosion by chemicals, mentioned above, were studied. Time was a very important factor, having an important influence on the destructive process in all samples.