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Limitations of the Fictive Temperature Concept
Author(s) -
RITLAND H. N.
Publication year - 1956
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.1151-2916.1956.tb15613.x
Subject(s) - borosilicate glass , thermodynamics , atmospheric temperature range , thermal expansion , thermal , kinetic energy , materials science , constant (computer programming) , transformation (genetics) , range (aeronautics) , mineralogy , chemistry , composite material , physics , classical mechanics , biochemistry , computer science , gene , programming language
The fictive temperature formalism, in which the structural state of the glass is characterized by the fictive temperature T , is very useful in the qualitative description of the effects of thermal treatment in the transformation range. Experimental data are presented which show, however, that such a one‐parameter description has only a limited quantitative significance. When samples of a borosilicate crown, glass, annealed at various constant cooling rates, are compared with samples annealed at constant temperature, it is found that a single parameter does not specify all physical properties simultaneously and that the two types of samples differ markedly in transformation‐range kinetic phenomena. Properties studied include density, refractive index, low‐temperature thermal expansion, approach to equilibrium at constant temperature, and thermal expansion during heating in the transformation range.