Investigating the role of iron and manganese oxides in colouring Post-Roman glass by XANES and micro-XRF spectroscopies

This research aims at studying colouring technologies in Post-Roman glass by correlating the impact of iron (Fe) and manganese (Mn) ratios and oxidation states. Some Anglo-Saxon glass vessels exhibit a dichroic character and display different colours despite having a similar chemical composition and concentrations of Fe and Mn oxides. Our goal is to study the colour change by looking at several glass production parameters, by using experimental glasses, that follow the composition of Post-Roman archaeological glass fragments from Tintagel castle (UK). Using bulk and micro Fe and Mn K-edge XANES combined with micro XRF spectroscopy will enable the characterisation of the oxidation state of Fe and Mn in fragments produced using different parameters, and the study of the dichroic character of the archaeological samples. The results will generate a deeper understanding of Fe and Mn interaction and redox reactions during glass production of archaeological glass assemblages of this type.