Glass forming regions, structure and properties of lanthanum barium germanate and gallate glasses

Made available in DSpace on 2022-04-28T19:41:41Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-11-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Horizon 2020 Framework Programme Agence Nationale de la Recherche Glass forming regions in the system GaO3/2 – GeO2 – LaO3/2 – BaO have been explored using aerodynamic levitation coupled to laser heating synthesis technique. Structure property relationships have been established between the thermal and optical properties of the resulting glass thanks to Raman and Infrared vibrational spectroscopies. The germano-gallate glass networks are mainly made of three-dimensional interconnected corner shared GeO4 and GaO4 tetrahedra forming Ge – O – Ge and Ga – O− – Ge bridges in which gallium tetrahedral GaO4 units are charged-compensated by barium and lanthanum cations. In GeO2-rich compositions, the excess of positive charges produces mainly non-bridging oxygens on germanate moieties, leading to a depolymerization of the glass network. In the case of gallium rich compositions, the infrared cut-off is red-shifted as compared to the germanate glasses, in accordance with the disappearance of germanium associated entities such as germanium and gallium bridges or germanium sites with non-bridging oxygen both vibrating at higher wavenumber. Institut de Chimie de la Matière Condensée de Bordeaux Université de Bordeaux, 87 Avenue du Dr Schweitzer Conditions Extrêmes et Matériaux Haute Température et Irradiation UPR3079 Université d'Orléans 1 Avenue de la Recherche Scientifique Institut des Sciences Moléculaires UMR 5255 Université́ de Bordeaux 351 cours de la Libération Institute of Chemistry São Paulo State University-UNESP Rua Prof. Francisco Degni, 55, CEP 14800-060 Institute of Chemistry São Paulo State University-UNESP Rua Prof. Francisco Degni, 55, CEP 14800-060 FAPESP: 2013/07793-6 FAPESP: 2019/01223-0 Horizon 2020 Framework Programme: 823941 Agence Nationale de la Recherche: ANR-10-IDEX-03-02 Agence Nationale de la Recherche: ANR-18-CE08-0004-02