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Conductivity Behavior of High‐Silica Glasses with Varied Concentrations of Sodium Ions
Author(s) -
SIMMONS CATHERINE J.,
SIMMONS JOSEPH H.
Publication year - 1979
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1979.tb19110.x
Subject(s) - enthalpy , conductivity , ion , diffusion , activation energy , thermodynamics , chemistry , nernst equation , sodium , thermal conduction , analytical chemistry (journal) , chromatography , physics , electrode , organic chemistry
The low‐frequency conductivity of silica glasses containing 5% B 2 O 3 and from 0.02 to 6.7% Na 2 O is extrapolated to dc values and analyzed in terms of temperature and concentration dependence. The concentration dependence of the conductivity occurs exclusively in the activation enthalpy. This prevents an analysis of the number of ions participating in the conduction in all but one sample for which tracer diffusion data gave a correlation factor of unity in the Nernst‐Einstein equation. The concentration dependence of the activation enthalpy was analyzed empirically. The activation enthalpy varies linearly with sodium‐sodium separation or jump distance. This result suggests that, at low Na concentrations, the conducting ions execute several separate motions between nonequilibrium sites before reaching the nearest equivalent site. The empirical equation is shown to fit activation energy data for silica glasses containing from 0.06 to 40% Na 2 O.