Structural investigation of hydrous sodium borosilicate glasses
- The structural properties of a borosilicate glass with nominal 16 mol% Na2O, 10 mol% B2O3 and 74mol% SiO2 and water contents between 0 and 8wt% H2O (0–22 mol% H2O)were investigated with IR, Raman and 11BMAS NMR spectroscopy. In addition to the pronounced OH stretching vibration band of weakly H-bonded species at 3580 cm−1 the MIR spectra show a triplet at 2900, 2350 and 1750 cm−1, similar as observed in water-bearing silicate glasses. These bands are assigned to OH groups and water molecules which are strongly H-bonded, to non-bridging oxygen. Water species contents determined from absorption bands in the NIR at 5200 cm−1 (molecular H2O), 4700 cm−1 (B\\OH), and 4500 cm−1 (Si\\OH) indicate that hydroxyl groups dominate up to ~6 wt% total H2O. Based on the absorption coefficients known from literature for silicate and borate glasses the B\\OH/Si\\OH ratio is estimated to be ≈0.8. As indicated by density, Raman and NMR data the incorporation ofwater has strong structural impacts inThe structural properties of a borosilicate glass with nominal 16 mol% Na2O, 10 mol% B2O3 and 74mol% SiO2 and water contents between 0 and 8wt% H2O (0–22 mol% H2O)were investigated with IR, Raman and 11BMAS NMR spectroscopy. In addition to the pronounced OH stretching vibration band of weakly H-bonded species at 3580 cm−1 the MIR spectra show a triplet at 2900, 2350 and 1750 cm−1, similar as observed in water-bearing silicate glasses. These bands are assigned to OH groups and water molecules which are strongly H-bonded, to non-bridging oxygen. Water species contents determined from absorption bands in the NIR at 5200 cm−1 (molecular H2O), 4700 cm−1 (B\\OH), and 4500 cm−1 (Si\\OH) indicate that hydroxyl groups dominate up to ~6 wt% total H2O. Based on the absorption coefficients known from literature for silicate and borate glasses the B\\OH/Si\\OH ratio is estimated to be ≈0.8. As indicated by density, Raman and NMR data the incorporation ofwater has strong structural impacts in particular at low water contents up to 3 wt% H2O. While the nominally dry glasses still contain a significant fraction (12%) of three-fold coordinated boron, almost all boron is four-fold coordinated in hydrous glasses. The increase of band components in the Raman spectra near 900 cm−1 relative to the region N 1050 cm−1 gives evidence for depolymerization of the network upon hydration. Fitting of the spectra with Gaussians implies that silica tetrahedra with two non-bridging oxygen (Q2) are preferentially formed by reactionwithwater on expense of tetrahedra linked to four tetrahedra (Q4).…
Autor*innen: | Ute Bauer, H. Behrens, Stefan ReinschORCiD, E. I. Morin, J. F. Stebbins |
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Dokumenttyp: | Zeitschriftenartikel |
Veröffentlichungsform: | Verlagsliteratur |
Sprache: | Englisch |
Titel des übergeordneten Werkes (Englisch): | Journal of Non-Crystalline Solids |
Jahr der Erstveröffentlichung: | 2017 |
Verlag: | Elsevier B. V. |
Jahrgang/Band: | 465 |
Erste Seite: | 39 |
Letzte Seite: | 48 |
DDC-Klassifikation: | Technik, Medizin, angewandte Wissenschaften / Ingenieurwissenschaften / Angewandte Physik |
Freie Schlagwörter: | Borosilicate glasses; Glass structure; Spectroscopy; Water-bearing glasses |
DOI: | 10.1016/j.jnoncrysol.2017.03.023 |
ISSN: | 0022-3093 |
ISSN: | 1873-4812 |
Verfügbarkeit des Dokuments: | Datei im Netzwerk der BAM verfügbar ("Closed Access") |
Datum der Freischaltung: | 30.06.2017 |
Referierte Publikation: | Ja |
Datum der Eintragung als referierte Publikation: | 30.06.2017 |