Thirteenth-century stained glass windows of the Sainte-Chapelle in Paris: An insight into medieval glazing work practices

•First large scale non-destructive study of Sainte-Chapelle (Paris) stained glasses.•Non-destructive study of ten panels by IBA and optical absorption spectroscopy.•Potash-lime silicate glass compositions typical from medieval glasses are found.•Sodium contents suggest at least two distinct origins of ancient glasses.•Colors and chemical compositions reveal use of common glass stock.