O vidro e os vitrais de edificações históricas de Belém: patologias e conservação

Abstract

The application of glass in Belém’s architecture, at first, was restricted to large buildings, in the late XIXth century, reaching its peak only in the next century, during the eclectic movement, as an import issue. However, face to the overexposure to the weather and improper substitutions, ancient glasses are gradually disappearing, almost being impossible to documentate it properly. In order to safeguard this material, the main objective of this research is to investigate technologically glasses and stained-glasses physico-chemical characteristics from buildings of Belém and its damages caused by weather conditions. Selected samples were characterized through optical microscopy, and scanning electron microscopy with energy dispersive X-ray microanalysis (SEM/EDX), concomitantly with the execution of graphic in order to do damage diagnosis and to identify most frequent pathologies. Therewith it was possible to verify that samples present a moderated level of degradation as considerable deposits of soot and discoloration and that the biofilm which develops at the glass surface is responsible for its opacity, that fact origins moderate corrosion and stains. FRX data revealed that all samples as soda-lime glass with 70% of SiO2. Resulting data will be important to subsidize conservation and restoration practices on historical glasses and stained-glasses according to local weather conditions.