title: Browning phenomenon of medieval stained glass windows.
abstract: In this work, three pieces of historical on-site glass windows dated from the 13th to 16th century and one archeological sample (8th century) showing Mn-rich brown spots at their surface or subsurface have been characterized by optical microscopy and Scanning Electron Microscopy coupled with Energy Dispersive X-ray spectroscopy. The oxidation state of Mn as well as the Mn environment in the alteration phase have been characterized by X-ray absorption spectroscopy at the Mn K-edge. Results show that the oxidation state of Mn and therefore the nature of the alteration phase varies according to the sample considered and is correlated with the extent of the brown alteration. The larger the brown areas the more oxidized the Mn. However, by contrast with literature, the samples presenting the more extended brown areas are not similar to pyrolusite and contain Mn mainly under a (+III) oxidation state.
authors: †Université Paris-Est, Laboratoire Géomatériaux et Environnement, (EA 4508),UPEM, 77454 Marne-la-Vallée, France.
authors: Jessica
authors: J
authors: Ferrand
authors: †Université Paris-Est, Laboratoire Géomatériaux et Environnement, (EA 4508),UPEM, 77454 Marne-la-Vallée, France.
authors: Stéphanie
authors: S
authors: Rossano
authors: ‡Laboratoire de Recherche des Monuments Historiques, 29 rue de Paris, 77420, Champs-sur-Marne, France.
authors: Claudine
authors: C
authors: Loisel
authors: ¶SOLEIL Synchrotron, l'Orme des merisiers St Aubin BP48, 91192 Gif-Sur-Yvette Cedex, France.
authors: Nicolas
authors: N
authors: Trcera
authors: †Université Paris-Est, Laboratoire Géomatériaux et Environnement, (EA 4508),UPEM, 77454 Marne-la-Vallée, France.
authors: Eric D
authors: ED
authors: van Hullebusch
authors: ‡Laboratoire de Recherche des Monuments Historiques, 29 rue de Paris, 77420, Champs-sur-Marne, France.
authors: Faisl
authors: F
authors: Bousta
authors: ‡Laboratoire de Recherche des Monuments Historiques, 29 rue de Paris, 77420, Champs-sur-Marne, France.
authors: Isabelle
authors: I
authors: Pallot-Frossard