Investigation of Glasses in the BaOB2O3GeO2 System with Low BaO Content by NMR and Raman Spectroscopy

Abstract

11B NMR and Raman scattering measurements are performed with glasses both, in the B2O3GeO2 and the BaOB2O3GeO2 systems. All glasses in the ternary system exhibit a constant molar concentration ratio of R = CBaO/CB2O3 = 0.25. It is shown that the six‐membered boron‐oxygen rings are not destroyed with GeO2 incorporation and the GeO4 tetrahedra are nearly randomly distributed between the tetraborate groups. The BO4 tetrahedra of the triborate units are found to be generally bonded to GeO4 tetrahedra. A possible explanation for the phase separation in the ternary system is proposed.

Structural Study of the Germanium–Aluminum–Borate Glasses by Solid State NMR and Raman Spectroscopies

“…With regard to the latter structural issues, borogermanate glasses usually do not present phase separation issues and thus appear particularly suitable for exploring network–former mixing effects within a micro- and macroscopically homogeneous medium. Despite this favorable situation very few structural studies are available in the literature, predominantly using spectroscopic tools such as vibrational spectroscopy and nuclear magnetic resonance. − To the present date, however, the powerful inventory of modern NMR methodology has been underutilized in the study of borogermanate glasses, leaving open many unanswered questions about their structural organization. From the viewpoint of network–former mixing effects, the present contribution is the first one addressing the connectivity analysis of modified borogermanate glasses.…”