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Dependence of the Fictive Temperature of Glass on Cooling Rate
Author(s) -
MOYNIHAN CORNELIUS T.,
EASTEAL ALLAN J.,
BOLT MARY ANN,
TUCKER JOSEPH
Publication year - 1976
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.1151-2916.1976.tb09376.x
Subject(s) - enthalpy , borosilicate glass , thermodynamics , relaxation (psychology) , glass transition , chemistry , activation energy , viscosity , differential scanning calorimetry , limiting , volume (thermodynamics) , materials science , physics , polymer , organic chemistry , mechanical engineering , psychology , social psychology , engineering
An equation derived by Ritland relating the cooling rate and fictive temperature for glasses without memory is extended to those with memory, i.e. those which exhibit a spectrum of relaxation times. Provided that the spectrum of relaxation times is temperature‐independent, the limiting fictive temperature, T′ f , obtained when a glass is cooled through the transition region, is shown to be related to the cooling rate, q , by d In | q |/ d (1/ T'f )=‐Δ h ★/ R where R is the ideal gas constant and Δ h ★ the activation enthalpy for the relaxation times controlling the structural relaxation. Values of T′ f vs q obtained from enthalpy measurements by differential scanning calorimetry are presented for B 2 O 3 , 0.4Ca(NO 3 ) 2 —0.6KNO 3 , and borosilicate crown glasses; Δ h ★ is equal, within experimental error, to the activation enthalpy for shear viscosity. Values of T′ f from volume and enthalpy measurements obtained at the same cooling rate for the borosilicate crown glass are equal.