article posted 1 April 2016
Myrtille Hunault graduated from both the ESPCI ParisTech and the University Pierre and Marie-Curie in Paris (2011). She did her PhD (2011–2014) research in the IMPMC in the University Pierre and Marie Curie under the supervision of Prof G. Calas and Dr. M. Hérold, on the colouring role Co2+ in medieval stained glass windows. She was then involved as a postdoctoral fellow in the 1-year transdisciplinary project “Convergence” granted by Sorbonne University, to study the colours of the 15th century rose of the Sainte-Chapelle of Paris being restored (2014–2015). Her research focuses on the colouring role of transition metal ions in glasses and crystals, using optical and synchrotron based x-ray spectroscopies and theoretical calculations. Since October 2015, she is a postdoctoral fellow in the group of Prof. F. de Groot in the University of Utrecht, the Netherlands.
Spectroscopy of transition metal ions in stained glass windows: from colour to history
Myrtille Hunault,*,1,2,5 Claudine Loisel,2 Fanny Bauchau,2 Claire Pacheco,3 Quentin Lemasson,3 Karine Boulanger,4 Michel Hérold4 & Georges Calas5
Most colours of medieval stained glass windows were obtained using transition metal (TM) elements. The richness of the colour palette is a relevant testimony of the high mastery of ancient glassmakers. Because the obtained colour depends on the elaboration conditions, glass composition (raw materials and colouring agents) and melting conditions, the determination of the subtle relations between chemistry and optical properties of glasses enables determining the history of art and glassmaking techniques. Among the spectroscopic methods used in glass science, optical absorption spectroscopy (OAS) enables to probe directly the origin of the glass colour and its link with the chemical composition of medieval glasses.
I will present a synthetic view of the colours of the early and late medieval stained glass windows of the Sainte-Chapelle of Paris, one of the most famous French gothic buildings. This approach relies on an unprecedented coupling between two non-invasive and non-destructive techniques: PIXE analysis on the AGLAE facility and a homemade portable visible-near infrared OAS setup .
The data obtained on historical glasses have been compared to model glasses with combined OAS and x-ray absorption spectroscopy (XANES and EXAFS) to determine the speciation (coordination number and oxidation state) of TM ions in these glasses. This enables to link the elaboration conditions to the final colour . Then by applying these tools to probe the speciation of the main TM: Fe, Mn, Cu and Co, in ancient glasses, I will present the inference of peculiar information about medieval glassmaking technologies [3–4].
Figure: Stained glass window panel D4 (detail) from the western rose of the Sainte-Chapelle of Paris, France (15th c.), showing typical colours. Blue, green and red glasses all contains copper, but in various oxidation states which will be discussed in this presentation (courtesy of Michel Hérold).
 M. Hunault, et al., Assessment of transition element speciation in glasses using a portable transmission UV-visible-NIR spectrometer, Appl. Spectrosc., 70  (2016).
 M. Hunault, et al., Local Ordering Around Tetrahedral Co2+ in Silicate Glasses, J. Am. Ceram. Soc., 97  60–62 (2014). doi:10.1111/jace.12709
 M. Hunault, et al. Spectroscopic Investigation of the Coloration and Fabrication Conditions of Medieval Blue Glasses, J. Am. Ceram. Soc., 99  89–97 (2016). doi:10.1111/jace.13783
 C. Loisel, et al. Revealing the fabrication technique of rare medieval stained glass from the Holy Chapel of Paris, in prep.).
University of Utrecht, Inorganic chemistry and catalysis group, Utrecht, The Netherlands
Centre de recherche sur la conservation, CNRS, MNHN, MCC, Laboratoire de Recherche des Monuments Historiques, Champs-sur-Marne, France
Centre de Recherche et de Restauration des Musées de France, Paris, France
Sorbonne Universités,Université Paris-Sorbonne, CNRS, MCC, Centre André Chastel, Paris, France
Sorbonne Universités, UPMC Univ Paris 06, CNRS, IRD, MNHN, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, Paris, France