DEVITRIFICATION BEHAVIOUR OF CORRODED GLASS: FOUR CASES STUDY

Abstract

This paper focuses on the devitrification behaviour and recrystallization mechanism of archaeological glass. It also aims to reveal the fact concerning this phenomenon as a deterioration process associated with glass corrosion. Many archaeological glasses attributed and dated to the early Islamic period in Egypt were collected and analyzed using XRD spectroscopy technique to identify the mineralogical composition and determine the crystalline phases present.A preliminary study by analytical scanning electron microscopy (SEM& EDX) allowed characterization of the elemental chemical composition of the underlying glasses and the neocrystallisation developed on their surfaces. Furthermore, the compositional phases and glass texture were also examined. According to the confirmed results obtained for four glasses, it can be concluded that the archaeological glass can be devitrified or partially recrystallize due to the corrosion process addition to the thermal effects. Many separated crystalline phases such as quartz, calcite, tosudite, jacopsite and calcium silicate were detected in the glass samples. This phenomenon considered one of the most dangerous deterioration aspects of corroded glass. So understanding it will assists the glass conservators in treating such corroded glass.