Influence of copper on the crystallization process of calcium antimonates in roman colored glass tesserae

Since antiquity, calcium antimonates crystals have been used for the glass opacification as they provide a white coloration to objects. Chromophores (3d transition elements) can be added during the manufacture of glass to bring new colors. We are interested in the study of opacification processes used for the manufacture of roman mosaic tesserae dating from the 4th century AD. We are interested in the influence of copper and its redox interactions with antimony on the crystallization kinetics. Laboratory-reproduced glasses of similar compositions to the tesserae studied were synthesized by varying the conditions of synthesis. The redox state quantification of Sb and Cu will be obtained by µXANES measurements within the glass matrix. These results can be compared to the same analyses performed on the white and turquoise roman tesserae. This study can be crucial to understand the manufacturing techniques used by master glassmakers for the manufacture of tesserae of roman mosaic colored.