title: Non-homogeneous distribution of Al3+in doped phosphate glasses revealed by27Al/31P solid state NMR.
abstract: Solid state NMR is applied in this contribution on the xAl2O3-(50-x/2)Na2O-(50-x/2)P2O5composition line (with 0<x<5mol%) in order to investigate the distribution of Al3+ions in Al2O3-doped sodium phosphate glasses. The structure was analysed by (i)27Al 1D-, 3Q-, DQ- MAS-NMR analysis and (ii) 1D31P,27Al(31P) 2D D-HMQC MAS-NMR and 2D31P R-INADEQUATE technique. The27Al NMR results confirm the presence of six-coordinated aluminate as major aluminate species and indicate that Al3+ions are fully dissociated in the glass network. The31P NMR data show the simultaneous presence of five different phosphate units connected to 0, 1 but also 2 Al3+ions and offer a new vision of the doping mechanism by highlighting a non-homogeneous distribution of Al3+ions in the phosphate matrix. This study indicates that the glass networks contain Al3+-rich and -poor domains and present thus a significant structural disorder beyond the local order.
authors.affiliation: LASIR UMR-CNRS 8516, Université de Lille 1, Villeneuve d'Ascq, France. Electronic address: gregory.tricot@univ-lille1.fr.
authors.forename: G
authors.initials: G
authors.lastname: Tricot
authors.affiliation: IMMCL, Université de Lille 1, Villeneuve d'Ascq, France.
authors.forename: B
authors.initials: B
authors.lastname: Doumert
authors.affiliation: LASIR UMR-CNRS 8516, Université de Lille 1, Villeneuve d'Ascq, France.
authors.forename: B
authors.initials: B
authors.lastname: Revel
authors.affiliation: LASIR UMR-CNRS 8516, Université de Lille 1, Villeneuve d'Ascq, France.
authors.forename: M
authors.initials: M
authors.lastname: Bria
authors.affiliation: IMMCL, Université de Lille 1, Villeneuve d'Ascq, France.
authors.forename: J
authors.initials: J
authors.lastname: Trebosc
authors.affiliation: LASIR UMR-CNRS 8516, Université de Lille 1, Villeneuve d'Ascq, France.
authors.forename: H
authors.initials: H
authors.lastname: Vezin
keywords: Correlation NMR; Inorganic glass; Structure