Early stages of glass alteration in the coastal atmosphere

Urban and industrial atmospheres can produce several damages on glass facades and historical stained-glass windows; however, the effect of coastal atmosphere on them has been scarcely studied. This work presents the results of the exposure of soda-lime, potash-lime, and mixed-alkali silicate glass to the coastal atmosphere in Cape Vilan (Galicia, Spain) at different distances to the coast (inland) during twelve months. Crystalline deposits were observed on all the samples, although their quantity depended on the meteorological conditions. The samples located nearest to the coast presented alteration layers, while those ones located farthest from the shore presented several isolated pits. Regarding the chemical composition, potash-lime silicate glass, typical composition from medieval glass windows, was the most altered glass in contrast to soda-lime and mixed-alkali silicate glasses.