Oxygen sites in silicate glasses: a new view from oxygen-17 NMR

Stebbins, Jonathan F.; Oglesby, Jane V.; Lee, S.K.

doi:10.1016/s0009-2541(00)00307-7

Cited by 62 publications

(40 citation statements)

References 48 publications

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“…Equation (4) has been used previously as well to estimate the NBO fraction in percalcic aluminosilicate systems. 26) In fact, the calculated NBO fraction was close to the value determined using 17 O MAS NMR spectroscopy (= 32.4 ± 0.3%) (see Fig. 5).…”

Section: Effect Of Degree Of Polymerization Of the Networksupporting

confidence: 83%

“…17 O MAS NMR Spectrum of 31.6CaO-44.2SiO2-13.4Al2O3-10.8K2O (mol%) Glass 17 O NMR spectroscopy is a powerful technique for elucidating the structure of aluminosilicate systems from an oxygen-centered view. 17,18) Because the cationic species in aluminosilicate glasses are linked by oxygen ions, the 17 O NMR signal can be used to determine the type of bonding species present in the test sample.…”

Section: 3mentioning

confidence: 99%

“…17,18) Because the cationic species in aluminosilicate glasses are linked by oxygen ions, the 17 O NMR signal can be used to determine the type of bonding species present in the test sample. The…”

Section: 3mentioning

confidence: 99%

“…The experiments were performed using the rotating crucible method over temperatures of 1 673-1 873 K. 17 O magic angle spinning nuclear magnetic resonance (MAS NMR) spectroscopy was used to identify the bonding species present in the investigated quaternary aluminosilicate system. The viscosity data were compared with the recently reported structural models of alkaline and alkaline earth aluminosilicate melts and glasses.…”

Section: Introductionmentioning

confidence: 99%

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Effect of Potassium Oxide Addition on Viscosity of Calcium Aluminosilicate Melts at 1673–1873 K

et al. 2014

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We investigated the changes induced in the viscosities of CaO-SiO2-Al2O3-K2O melts (CaO/SiO2 molar ratio = 0.68 ± 0.04, Al2O3 content = 13.4 ± 0.6 mol%) with the addition of K2O in amounts of 0-17.4 mol% for temperatures of 1 673-1 873 K using the rotating crucible method. The viscosity increased with an increase in the K2O content when K2O/Al2O3 molar ratio < 0.7. On the other hand, the viscosity decreased with the addition of K2O for K2O/Al2O3 molar ratio > 0.9. The maximum values of the viscosities were noticed in the range of 0.7 < K2O/Al2O3 molar ratio < 0.9. This behavior could not be explained on the basis of the polymerization degree of the aluminosilicate network structure. The 17 O magic angle spinning nuclear magnetic resonance (MAS NMR) spectrum of the 31.6CaO-44.2SiO2-13.4Al2O3-10.8K2O (mol%) glass suggested that K + ions preferentially compensate the negative charge of AlO4, while the Ca 2+ ions primarily create non-bridging oxygens (NBOs). The viscosity data and the 17 O MAS NMR spectrum also suggested that the increase in viscosity for K2O/Al2O3 molar ratio < 0.7 was because of the increase in the average bond strength of the aluminosilicate framework, which was attributable to the substitution of Ca 2+ ions by K + ions at the charge compensator sites. The activation energies for viscous flow indicated that the NBOs bonded with K + ions, forming NBO-K species, for K2O contents greater than those corresponding to the viscosity maxima. Thus, the viscosities of aluminosilicate melts are indicative of the average bond strengths of the melts.KEY WORDS: viscosity; K-Ca aluminosilicate melts and glasses;17 O MAS NMR spectroscopy.

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Section: Effect Of Degree Of Polymerization Of the Networksupporting

confidence: 83%

Section: 3mentioning

confidence: 99%

Section: 3mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effect of Potassium Oxide Addition on Viscosity of Calcium Aluminosilicate Melts at 1673–1873 K

et al. 2014

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“…This can be done via a range of techniques which include NMR spectroscopy (e.g. Stebbins 1991;Stebbins and McMillan 1993;Stebbins and Xu 1997;Stebbins et al 2001); diffusion measurements (e.g. Liu et al 1988) and mechanical spectroscopy (e.g.…”

Section: Introductionmentioning

confidence: 99%

Shear modulus, heat capacity, viscosity and structural relaxation time of Na2O–Al2O3–SiO2 and Na2O–Fe2O3–Al2O3–SiO2 melts

Falenty

Webb

2010

Phys Chem Minerals

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The configurational heat capacity, shear modulus and shear viscosity of a series of Na 2 O-Fe 2 O 3 -Al 2 O 3 -SiO 2 melts have been determined as a function of composition. A change in composition dependence of each of the physical properties is observed as Na 2 O/(Na 2 O ? Al 2 O 3 ) is decreased, and the peralkaline melts become peraluminous and a new charge-balanced Al-structure appears in the melts. Of special interest are the frequency dependent (1 mHz-1 Hz) measurements of the shear modulus. These forced oscillation measurements determine the lifetimes of Si-O bonds and Na-O bonds in the melt. The lifetime of the Al-O bonds could not, however, be resolved from the mechanical spectrum. Therefore, it appears that the lifetime of Al-O bonds in these melts is similar to that of Si-O bonds with the Al-O relaxation peak being subsumed by the Si-O relaxation peak. The appearance of a new Al-structure in the peraluminous melts also cannot be resolved from the mechanical spectra, although a change in elastic shear modulus is determined as a function of composition. The structural shear-relaxation time of some of these melts is not that which is predicted by the Maxwell equation, but up to 1.5 orders of magnitude faster. Although the configurational heat capacity, density and shear modulus of the melts show a change in trend as a function of composition at the boundary between peralkaline and peraluminous, the deviation in relaxation time from the Maxwell equation occurs in the peralkaline regime. The measured relaxation times for both the very peralkaline melts and the peraluminous melts are identical with the calculated Maxwell relaxation time. As the Maxwell equation was created to describe the timescale of flow of a mono-structure material, a deviation from the prediction would indicate that the structure of the melt is too complex to be described by this simple flow equation. One possibility is that Al-rich channels form and then disappear with decreasing Si/Al, and that the flow is dominated by the lifetime of Si-O bonds in the Al-poor peralkaline melts, and by the lifetime of Al-O bonds in the relatively Si-poor peralkaline and peraluminous melts with a complex flow mechanism occurring in the mid-compositions. This anomalous deviation from the calculated relaxation time appears to be independent of the change in structure expected to occur at the peralkaline/peraluminous boundary due to the lack of charge-balancing cations for the Al-tetrahedra.

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Methoden der Festk��rper-NMR-Spektroskopie in der Chemie

2002

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A. Jerschow et al. und 29 Si. Wir behandeln daher zun‰chst die Spinwechselwirkungen, die bei solchen Kernen eine Rolle spielen, und stellen spektroskopische Methoden vor, mit denen sich diese Wechselwirkungen zur Vereinfachung der Spektren beeinflussen oder gar ausschalten lassen.In einem einfachen Beispiel wird eine w‰ssrige Lˆsung von 1-13 C-markiertem (10 %) Glycin mit einem p/2-Einzelpuls der Resonanzfrequenz von 13 C-Kernen bestrahlt. In dem resultierenden Spektrum (Abbildung 1) beobachtet man zwei gut aufgelˆste Signale, die den 13 C-angereicherten Carbonyl-C-Atomen und den in nat¸rlicher Isotopenverteilung (ca. 1 % 13

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Oxygen sites in silicate glasses: a new view from oxygen-17 NMR

Cited by 62 publications

References 48 publications

Effect of Potassium Oxide Addition on Viscosity of Calcium Aluminosilicate Melts at 1673–1873 K

Effect of Potassium Oxide Addition on Viscosity of Calcium Aluminosilicate Melts at 1673–1873 K

Shear modulus, heat capacity, viscosity and structural relaxation time of Na2O–Al2O3–SiO2 and Na2O–Fe2O3–Al2O3–SiO2 melts

Methoden der Festk��rper-NMR-Spektroskopie in der Chemie

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