Long term assessment of atmospheric decay of stained glass windows

Abstract Several studies indicate that the decay of medieval stained glass windows is related to both the glass composition and the characteristics of the environment. The kinetics of the decay processes has been always described through experiences performed in aqueous confined conditions, which are obviously not encountered in real condition. A research programme has been set up in order to assess the kinetics of atmospheric weathering. The long and short term weathering has been studied through respectively ancient glass fragments and glass analogues exposed in the field. This paper presents the preliminary results of the long term. A characterisation of the morphology and chemical modification induced by weathering has been performed. Results will be used in the next step to build up a model of long term atmospheric weathering kinetics.