TY - JOUR
T1 - Structural characterization of Eu2O3-MgO-Na2O-Al2O3-SiO 2 glasses with varying Eu2O3 content
T2 - Raman and NMR studies
AU - Utegulov, Zhandos N.
AU - Eastman, Margaret A.
AU - Prabakar, S.
AU - Mueller, Karl T.
AU - Hamad, Abdulatif Y.
AU - Wicksted, James P.
AU - Dixon, George S.
N1 - Funding Information:
The authors thank Dr Joel Martin and Mr Charles Hunt for preparing some of the glass samples. This work was supported in part by the US Army Research Office under Grant # DAAHO4-96-1-0322 and the National Science Foundation under Grant # DMP9705284. Funds for the Oklahoma Statewide Shared NMR Facility were provided by the National Science Foundation (BIR-9512269), the Oklahoma State Regents for Higher Education, the W.M. Keck Foundation and Conoco Inc. K.T.M is supported by a Camille Dreyfus Teacher-Scholar Award. The 500 MHz spectrometer at Penn State University was acquired with support from the National Science Foundation (CHE-9601572).
PY - 2003/1
Y1 - 2003/1
N2 - Raman, 27Al and 29Si NMR spectroscopies are used to investigate the structure of [0.15Na2O-0.12MgO-0.03Al2O3-0.70SiO2 ](100-x): [Eu2O3]x glasses with varying Eu2O3 content (x = 0, 0.73, 1.26, 3.90, 5.26 and 8.11 mol%). Spectral changes in the Raman envelope at (900-1240) cm-1 indicate that the number of silica tetrahedra with more than one non-bridging oxygen (NBO) per tetrahedron and the number of silica tetrahedra with one NBO associated with Eu increase with increasing rare-earth concentration. 29Si MAS NMR spectra show a single broad peak with maxima at frequencies attributable to a predominance of Q3 species. Quantitative 27Al and 29Si NMR spectroscopies show that aluminum and silicon species become less observable as Eu2O3 content increases, presumably due to interactions with paramagnetic europium. The 27Al NMR spectra reveal the presence of only tetrahedrally coordinated Al sites, with a gradual increase in the structural disorder associated with these sites as the concentration of Eu2O3 increases. This is in agreement with the appearance of the broad Raman band at 790 cm-1 attributed to Al-O stretching vibrations with Al in fourfold coordination.
AB - Raman, 27Al and 29Si NMR spectroscopies are used to investigate the structure of [0.15Na2O-0.12MgO-0.03Al2O3-0.70SiO2 ](100-x): [Eu2O3]x glasses with varying Eu2O3 content (x = 0, 0.73, 1.26, 3.90, 5.26 and 8.11 mol%). Spectral changes in the Raman envelope at (900-1240) cm-1 indicate that the number of silica tetrahedra with more than one non-bridging oxygen (NBO) per tetrahedron and the number of silica tetrahedra with one NBO associated with Eu increase with increasing rare-earth concentration. 29Si MAS NMR spectra show a single broad peak with maxima at frequencies attributable to a predominance of Q3 species. Quantitative 27Al and 29Si NMR spectroscopies show that aluminum and silicon species become less observable as Eu2O3 content increases, presumably due to interactions with paramagnetic europium. The 27Al NMR spectra reveal the presence of only tetrahedrally coordinated Al sites, with a gradual increase in the structural disorder associated with these sites as the concentration of Eu2O3 increases. This is in agreement with the appearance of the broad Raman band at 790 cm-1 attributed to Al-O stretching vibrations with Al in fourfold coordination.
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U2 - 10.1016/S0022-3093(02)01594-6
DO - 10.1016/S0022-3093(02)01594-6
M3 - Article
AN - SCOPUS:6444245491
SN - 0022-3093
VL - 315
SP - 43
EP - 53
JO - Journal of Non-Crystalline Solids
JF - Journal of Non-Crystalline Solids
IS - 1-2
ER -