Examination of the mixed-alkali effect in (Li,Na) disilicate glasses by nuclear magnetic resonance and conductivity measurements

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Abstract

Results from 29Si, 23Na and 7Li magic-angle spinning nuclear magnetic resonance (NMR) spectroscopy, 7Li NMR relaxation and electrical conductivity in a series of [Li(1 − x) · Nax]2O · 2SiO2 (disilicate) glasses are used to investigate the mixed-alkali effect. From the 29Si NMR spectra there is relatively little change of the network with alkali composition. 23Na and 7Li NMR linewidths and shifts change continuously as a function of composition, indicating that the alkali ions are intimately and uniformly mixed rather than separated into lithium and sodium-rich domains. The activation energy from electrical conductivity shows a distinct maximum at the central composition (x = 0.5), whereas the local activation energy for lithium motion determined from NMR shows only a smaller but monotonic increase as the lithium-content decreases.

References (35)

  • D.E. Day

    J. Non-Cryst. Solids

    (1976)
  • G.N. Greaves et al.

    J. Non-Cryst. Solids

    (1994)
  • R. Dupree et al.

    J. Non-Cryst. Solids

    (1986)
  • H. Maekawa et al.

    J. Non-Cryst. Solids

    (1991)
  • J.F. Emerson et al.

    J. Non-Cryst. Solids

    (1989)
  • R. Dupree et al.

    J. Non-Cryst. Solids

    (1990)
  • H. Eckert

    Progr. NMR Spectrosc.

    (1992)
  • P.J. Bray et al.

    J. Non-Cryst. Solids

    (1991)
  • J.F. Emerson et al.

    J. Non-Cryst. Solids

    (1994)
  • W. Hater et al.

    J. Non-Cryst. Solids

    (1989)
  • K.L. Ngai et al.

    Solid State Ionics

    (1992)
  • E. Gobel et al.

    J. Magn. Reson.

    (1979)
  • K.L. Funke et al.

    Solid State Ionics

    (1990)
  • K.L. Funke

    J. Non-Cryst. Solids

    (1994)
  • O. Kanert et al.

    J. Non-Cryst. Solids

    (1991)
  • R.D. Williams et al.

    J. Non-Cryst. Solids

    (1992)
  • S.C. Kohn et al.

    Geochim. Cosmochim. Acta

    (1989)
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