TY - JOUR A1 - Koudelka, L. A1 - Mosner, P. A1 - Zeyer-Düsterer, Michaela A1 - Jäger, Christian ED - Brooks, H. T1 - Study of potassium-zinc borophosphate glasses N2 - Potassium–zinc borophosphate glasses were prepared and studied in two compositional series xK2O–(50–x)ZnO–10B2O3–40P2O5 and xK2O–(50–x)ZnO–20B2O3–30P2O5 with x = 0, 10, 20, 30, 40 and 50 mol% K2O. The replacement of zinc by potassium decreases the density and increases the molar volume of these glasses, whereas glass transition temperature and chemical durability decrease with increasing potassium content. Structural changes were studied by 11B and 31P MAS NMR and Raman spectroscopy. The observed changes in the spectra and the properties of the studied glasses can be ascribed to several reasons and namely to the differences in the space occupied by cations Zn2+ and 2K+, the differences in the electronegativity of zinc and potassium and a large difference in the field strength of Zn2+ and K+ cations and thus higher ionicity of K–O bonds in comparison with Zn–O bonds. KW - A. Glasses KW - C. Raman spectroscopy KW - D. Nuclear magnetic resonance PY - 2007 DO - https://doi.org/10.1016/j.jpcs.2007.02.012 SN - 0022-3697 VL - 68 IS - 4 SP - 638 EP - 644 PB - Pergamon Press CY - New York, NY AN - OPUS4-17579 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Koudelka, L. A1 - Mosner, P. A1 - Zeyer, M. A1 - Jäger, Christian T1 - Structural study of PbO-B2O3-P2O5 glasses by NMR, Raman and infrared spectroscopy T2 - 19th International Congress on Glass CY - Edinburgh, Scotland, UK DA - 2001-07-01 PY - 2002 SN - 0-900682-39-6 N1 - Serientitel: Physics and chemistry of glasses – Series title: Physics and chemistry of glasses VL - 43C IS - 43C.2002 SP - 1 EP - 6 PB - Soc. of Glass Techn. CY - Sheffield AN - OPUS4-11012 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Koudelka, L. A1 - Mosner, P. A1 - Zeyer, M. A1 - Jäger, Christian T1 - Structure and properties of mixed sodium-lead borophosphate glasses N2 - Mixed sodium–lead borophosphate glasses were prepared in two compositional series xNa2O–(50 - x)PbO–10B2O3–40P2O5 and xNa2O–(50 - x)PbO–20B2O3–30P2O5 with x = 0, 10, 20, 30, 40 and 50 mol% Na2O. Their density decreases and molar volume increases slightly with increasing Na2O content. Chemical durability decreases steeply for glasses containing 40–50 mol% Na2O, whereas glass transition temperatures reveals a minimum at the glasses with 30–40 mol% Na2O. The 31P MAS NMR and Raman spectra of the first series show that with increasing Na2O content the ratio of structural units Q2/Q1 slowly increases and the Q2 phosphate units and BO4 units prevail in the structure of these glasses. In the second series of glasses Q1 diphosphate units together with BO4 and small number of BO3 units form structural network of glasses. The replacement of PbO by Na2O results in higher ionicity of bonding interactions between compensating cations and the anionic network. The lower cation field strength of Na+ ions results in the observed downfield shift of ? (31P) values in Na-rich glasses and narrower vibrational bands in their Raman spectra. PY - 2005 DO - https://doi.org/10.1016/j.jnoncrysol.2005.01.015 SN - 0022-3093 VL - 351 IS - 12-13 SP - 1039 EP - 1045 PB - North-Holland Publ. Co. CY - Amsterdam AN - OPUS4-11016 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Koudelka, L. A1 - Mosner, P. A1 - Zeyer, M. A1 - Jäger, Christian T1 - Lead borophosphate glasses doped with titanium dioxide N2 - Glasses of the compositional series of 50PbO–yB2O3–(50-y)P2O5–xTiO2 (with x=0–16) have been prepared and characterized by the determination of density, molar volume, glass transition temperature, dilatation softening temperature, thermal and chemical durability. Structural changes were evaluated from the studies by 31P and 11B MAS NMR, Raman and infrared spectroscopy. Molar volume of the glasses decreases and the glass transition temperature increases with increasing additions of TiO2. 31P MAS NMR spectra revealed that titanate units enter phosphate chains decreasing the number of Q2 units and increasing the number of Q1 units. This result is confirmed by the observed changes in the Raman and infrared spectra of the TiO2-doped glasses. PY - 2003 DO - https://doi.org/10.1016/S0022-3093(03)00380-6 SN - 0022-3093 VL - 326-327 SP - 72 EP - 76 PB - North-Holland Publ. Co. CY - Amsterdam AN - OPUS4-11020 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Koudelka, L. A1 - Mosner, P. A1 - Petrík, J. A1 - Zeyer, M. A1 - Jäger, Christian T1 - Study of the structure of mixed lead borophosphate glasses by NMR, RAMAN and IR Spectroscopy PY - 2002 SN - 0918-4783 VL - 13 SP - 165 EP - 170 CY - Tokyo AN - OPUS4-11021 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Koudelka, L. A1 - Mosner, P. A1 - Jirák, J. A1 - Zeyer-Düsterer, Michaela A1 - Jäger, Christian T1 - Medium range order in lead borophosphate glasses N2 - The structure of 50PbO-xB2O3-(50-x)P2O5 glasses with x=0-25 mol% B2O3 was refined by Raman and 11B MQMAS NMR. The analysis of Raman spectra, using the concentration step of 2 mol% B2O3 within the range of 0-12 mol% B2O3, showed that the evolution of changes in the type of oxygen bridges can be observed from the Raman bands within the range of 600-800 cm-1. 11B MQMAS NMR spectra of glasses with x=15, 20 and 25 mol% B2O3 revealed the presence of two BO4 sites in these glasses. The first site B1O4, characterised by the chemical shift of d=-3·8 — (-3·4) ppm, was assigned to tetrahedral B(OP)4 structural units. Within the concentration range x=15-25 mol% B2O3, the site B1O4 is gradually replaced by the site B2O4 with the chemical shift of d=-1·8 — (-1·1) ppm. This second site was assigned to the presence of B(OP)3(OB) units in which the central boron atom is linked to three PO4 groups and one BO3 group. KW - NMR KW - Raman KW - Struktur KW - Gläser PY - 2006 SN - 0031-9090 VL - 47 IS - 4 SP - 471 EP - 475 PB - Thornton CY - Sheffield AN - OPUS4-14811 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -