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Title: Linking high-pressure structure and density of albite liquid near the glass transition

Authors:
; ; ;  [1];  [2];  [2]
  1. (UCD)
  2. (
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
Sponsoring Org.:
National Science Foundation (NSF)
OSTI Identifier:
1173007
Resource Type:
Journal Article
Resource Relation:
Journal Name: Geochim. Cosmochim. Acta; Journal Volume: 157; Journal Issue: 05, 2015
Country of Publication:
United States
Language:
ENGLISH

Citation Formats

Gaudio, Sarah J., Lesher, Charles E., Maekawa, Hideki, Sen, Sabyasachi, Aarhus), and Tohoku). Linking high-pressure structure and density of albite liquid near the glass transition. United States: N. p., 2015. Web. doi:10.1016/j.gca.2015.02.017.
Gaudio, Sarah J., Lesher, Charles E., Maekawa, Hideki, Sen, Sabyasachi, Aarhus), & Tohoku). Linking high-pressure structure and density of albite liquid near the glass transition. United States. doi:10.1016/j.gca.2015.02.017.
Gaudio, Sarah J., Lesher, Charles E., Maekawa, Hideki, Sen, Sabyasachi, Aarhus), and Tohoku). Fri . "Linking high-pressure structure and density of albite liquid near the glass transition". United States. doi:10.1016/j.gca.2015.02.017.
@article{osti_1173007,
title = {Linking high-pressure structure and density of albite liquid near the glass transition},
author = {Gaudio, Sarah J. and Lesher, Charles E. and Maekawa, Hideki and Sen, Sabyasachi and Aarhus) and Tohoku)},
abstractNote = {},
doi = {10.1016/j.gca.2015.02.017},
journal = {Geochim. Cosmochim. Acta},
number = 05, 2015,
volume = 157,
place = {United States},
year = {Fri May 01 00:00:00 EDT 2015},
month = {Fri May 01 00:00:00 EDT 2015}
}
  • Cited by 12
  • The authors have measured the relative enthalpy, H/sub T/ - H/sub 300K//sup glass/, and the heat capacities of CaMgSi/sub 2/O/sub 6/ (Di) stable liquid and glass; of KAlSi/sub 3/O/sub 8/ (Sa) stable and supercooled liquid and glass; of NaAlSi/sub 3/O/sub 8/ (Ab) liquid derived directly by melting solid albite; of crystalline, disordered albite itself; and of NaAlSiO/sub 4/ (Ne) liquid and glass. The authors have also determined the effect of annealing at 981 K on the enthalpy of the glasses quenched from liquids at high temperature. This effect is relatively small, ranging from 0 to 1100 cal/mol. Albite liquid preparedmore » by melting of the crystalline phase has a heat capacity and relative enthalpy indistinguishable from those of a liquid produced by heating the glass. The enthalpy of crystalline, disordered albite is equal to that predicted by heat capacity data collected below 1000 K for the triclinic phase by Hemingway et al (1981). The liquid heat capacities of Ab and Sa (88.2 and 89.5 ca/mol x K) are nearly equal and are much lower than that for An liquid (113 cal/mol x K), suggesting that the latter undergoes greater structural changes, possibly depolymerization, with increasing T. The entropies of fusion of Ab and Sa (10.9 and 9.4 cal/mol x K) are similar, and much of the difference between these values and that for An (17.7 cal/mol x K) could be due to Al/Si order in crystalline An. 55 references, 4 figures, 7 tables.« less
  • To investigate the effects of local density fluctuations on phonon propagation in a hydrogen bonded structure, we studied the thermal conductivity κ of the crystal, liquid, and glassy states of pure glycerol as a function of the temperature, T, and the pressure, p. We find that the following: (i) κ{sub crystal} is 3.6-times the κ{sub liquid} value at 140 K at 0.1 MPa and 2.2-times at 290 K, and it varies with T according to 138 × T{sup −0.95}; (ii) the ratio κ{sub liquid} (p)/κ{sub liquid} (0.1 MPa) is 1.45 GPa{sup −1} at 280 K, which, unexpectedly, is about themore » same as κ{sub crystal} (p)/κ{sub crystal} (0.1 MPa) of 1.42 GPa{sup −1} at 298 K; (iii) κ{sub glass} is relatively insensitive to T but sensitive to the applied p (1.38 GPa{sup −1} at 150 K); (iv) κ{sub glass}-T plots show an enhanced, pressure-dependent peak-like feature, which is due to the glass to liquid transition on heating; (v) continuous heating cold-crystallizes ultraviscous glycerol under pressure, at a higher T when p is high; and (vi) glycerol formed by cooling at a high p and then measured at a low p has a significantly higher κ than the glass formed by cooling at a low p. On heating at a fixed low p, its κ decreases before its glass-liquid transition range at that p is reached. We attribute this effect to thermally assisted loss of the configurational and vibrational instabilities of a glass formed at high p and recovered at low p, which is different from the usual glass-aging effect. While the heat capacity, entropy, and volume of glycerol crystal are less than those for its glass and liquid, κ{sub crystal} of glycerol, like its elastic modulus and refractive index, is higher. We discuss these findings in terms of the role of fluctuations in local density and structure, and the relations between κ and the thermodynamic quantities.« less
  • Recent redetermination of the melting curve of albite, NaAlSi/sub 3/O/sub 8/, has raised questions about possible nonequilibrium states in viscous silicate liquids near their liquidus temperatures and about the thermodynamic description of albite melt at high P and T. Solid solubility of excess nepheline in albite, and of excess silica in anorthite and celsian (on the order of 1-4 wt %) has been reported in the literature. In analogy to similar cases in semiconductors, it is proposed that this homogeneity range of the feldspar phase (from approximately X/sub NaAlO/sub 2// = 0.245 to X/sub NaAlO/sub 2// = 0.27 in themore » SiO/sub 2/-NaAlO/sub 2/ system) may explain the melting behavior if the composition of maximum melting point does not correspond to stoichiometric NaAlSi/sub 3/O/sub 8/ (X/sub NaAlO/sub 2// = 0.25). A schematic phase diagram is proposed in which stoichiometric NaAlSi/sub 3/O/sub 8/ melts over a temperature interval (1100-1120/sup 0/C), and the composition of maximum melting point (more nepheline-rich than albite) has its liquidus near 1145/sup 0/C. Calorimetric experiments, using both solution calorimetry in molten 2PbO.B/sub 2/O/sub 3/ and transposed temperature drop calorimetry, show that the difference in enthalpy between albite glasses quenched from melts at different temperatures is very small. The complication introduced by a possible solid solution range in crystalline albite may influence its pressure-temperature melting relations. However, even if one neglects this effect, the thermodynamic data (heat and volume of fusion of albite at atmospheric pressure) may be reconciled with the slope of the melting curve at P>10 kbar if one assumes a compression of the melt arising from structural change. The magnitude of this volume change is estimated and is comparable to that found for glasses quenched from 15-25 kbar and temperatures above the melting curve.« less
  • A model is presented for supercooled liquids above the liquid-glass transition containing long-lived order parameter fluctuations, though no average order. The order parameter fluctuations (OPF) are those which would have led to crystallization if their size and concentration had not been kinetically arrested. Being more dense than the isotropic fluid, the regions containing fluctuations are more rigid and relax more slowly. Concentrations of OPF are spatially varying and cause excess light scattering and depolarization, both of which are seen experimentally in polymeric and nonpolymeric glasses. A free energy mismatch between the isotropic fluid and the OPF causes the mixture tomore » attempt to separate into OPF-rich and isotropic-rich fluid phases. As temperature falls mobility is lost; mobile defects in the isotropic fluid control the structural relaxation. This defect diffusion mechanism leads directly to Kohlrausch-Williams/Watts decay, and the phase separation process results in a generalized Vogel-Flucher or WLF temperature dependence as defects cluster and lose mobility. Predictions for the Landau-Placzek ratio and the Vogel behavior agree well with experimental for o-terphenyl. Scaling relations, analogous to those found from mode coupling theories, exist between the {alpha} and {beta} processes, though with different exponents. 26 refs., 3 figs.« less