Múzeumi műtárgyvédelem 2., 1975 (Múzeumi Restaurátor És Módszertani Központ)
Szalay Zoltán: Az üveg romlásának okairól
Zoltán Szalay THE CAUSES OP GLASS DETERIORATION Summary The author summarizes the causes of glass deterioration. A historical review os given about the different glass theoretical considerations. Theoretically it is supposed that two crystalline structures exists in the glasses, but these structures are not perfectly developed. The materials of glass production and the general compositions of glasses are referred. The glass surfaces are suffering specific alterations under external effects (mechanical, chemical and so on). Under moisture effects different coatings (e.g. carbonated alkali oxydes) may develop on their surface. The impurities of glass surfaces favour the deterioration of glasses. Firstly microcraters come into being and later, as these meet, laminar layers are developing which accelerate the deterioration. During the deglassifying process the quasicrystalline lattice structure slowly became arranged. The speed of the arrangement depends on the temperature and composition. Especially the glasses containing much of alkali are subject to hydrolytic deteriorations. The form of the deterioration may be laminar or homogeneous or may be of splinters or scales. The disintegration products are calcium carbonate and silicon dioxyde. The corrosion of glass is favoured by different ions, mainly by NH^ and P0^~ ions.- 177
