Glass disease: causes, effects and treatments (EnViCET project)

4th International Congress on Science and Technology for the Conservation of Cultural Heritage

Glass pieces from the Real Fábrica de Cristales de San Ildefonso (La Granja de San Ildefonso, Segovia, Spain) have an important worldwide reputation; nevertheless, not all of them have the same good quality. After the Spanish War of Independence, the production technology in the factory changed and began to produce objects with high artistic value, but with poor chemical resistant glass, which can be degraded by the environmental humidity and the volatile organic compounds emitted by wooden showcases and cabinets. The Royal Palace of Madrid and the Technological Museum of Glass (La Granja de San Ildefonso, Spain) treasure pieces produced with this unstable glass and, most of them, present the pathology known as crizzling or “glass disease”. This pathology is a serious conservation problem because there is no way to stop or to reverse the damage, just to minimize the alteration rate by means of a strict environmental control. Unfortunately, implementing such a control in a museographic space is complicated due to both the museum features and economic investment. Therefore, this “disease” could destroy the high-quality glass objects that were manufactured with the purpose of being “pride of Spaniards” after the war. This project aims to be a systematic approach to the crizzling pathology through the historical and environmental study of the original glass pieces, the identification of the alteration mechanism in model glasses, and the evaluation of the most common conservation treatments. The innovative contribution of the project to the conservation of the European glass heritage concerns the alteration pathologies of glassware and decoration objects. In fact, apart from the studies about famous Venetian glass objects, most of research has been focussed on stained glass windows and archaeological glass, while very little attention has been paid to decorative glass objects.