Structure and properties of gallium-rich sodium germano-gallate glasses

Téa Skopak (1, 2) , Scott Kroeker (3) , Kirill Levin (3) , Marc Dussauze (4) , Raphaël Méreau (4) , Yannick Ledemi (2, 5) , Thierry Cardinal (1) , Evelyne Fargin (1) , Younès Messaddeq (5, 2)

1 ICMCB - Institut de Chimie de la Matière Condensée de Bordeaux
2 COPL - Centre d'Optique, Photonique et Laser
3 Department of Chemistry
4 ISM - Institut des Sciences Moléculaires
5 ULaval - Université Laval [Québec]

Glass compositions in the gallium-rich region of the ternary GaO3/2–GeO2–NaO1/2 vitreous system are studied as a function of the Na/Ga cationic ratio (ranging from 1.30 to 1.61) for a fixed GeO2 content. Glass structures are investigated by 71Ga magic angle spinning nuclear magnetic resonance, infrared, and Raman spectroscopies, and the thermal, optical, and physical properties are characterized. Vibrational spectra are interpreted with the help of density functional theory calculations. Gallium oxide generally enters the germania network in fourfold coordination, however, for a Na/Ga ratio below unity, gallium cations tend to charge balance with the formation of five- or six-fold coordination units. When the amount of sodium is greater than gallium, nonbridging oxygens are formed preferably on germanate tetrahedral units. These structural descriptions are used to understand the evolution of glass properties such as glass transition temperature, density, and refractive index.

Mots clés: 71Ga NMR spectroscopy; vibrational spectroscopy; infrared; germano-gallate glasses; 71 Ga NMR spectroscopy; glass structure

Domaines: Matériaux

Téa Skopak, Scott Kroeker, Kirill Levin, Marc Dussauze, Raphaël Méreau, et al.. Structure and properties of gallium-rich sodium germano-gallate glasses. Journal of Physical Chemistry C, 2019, 123 (2), pp.1370-1378. ⟨10.1021/acs.jpcc.8b08632⟩. ⟨hal-02048674⟩