Looking through model medieval green glasses: From color to recipe
- Synchrotron SOLEIL Gif‐sur‐Yvette France
- Laboratoire de Recherche des Monuments Historiques Ministère de la Culture Champs‐sur‐Marne France, Centre de Recherche sur la Conservation (CRC) Muséum National d'Histoire Naturelle CNRS Ministère de la Culture Paris France
Abstract The colors of medieval stained glasses depend on their chemical composition. The redox interactions in glass between iron and copper and their influence on the color were investigated in two soda‐lime silicate model glasses. Both glasses have close iron and copper redox ratios and copper oxidizes iron when the iron content is smaller than the copper content. The redox speciation of iron and copper was determined using combining x‐ray and optical absorption spectroscopies in relation with the resulting color. The molar extinction coefficient of Cu 2+ was estimated from the combined analysis to be 32 mol/L/cm. The glass color change from green to blue‐green color is assigned to the decrease of the total iron content, confirming that ancient glassmakers could control the final color with the glass recipe. These results provide reference data for further spectroscopic investigations of medieval stained glasses. Comparison with ancient copper‐colored green glass compositions suggests that the higher ratio of copper to iron total contents was imposed by the more reducing melting conditions in medieval furnaces.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 1603683
- Journal Information:
- International Journal of Applied Glass Science, Journal Name: International Journal of Applied Glass Science Vol. 11 Journal Issue: 3; ISSN 2041-1286
- Publisher:
- Wiley-BlackwellCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
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