Title of article :
Specific heat relaxation-based critique of isothermal glass transition, zero residual entropy and time-average formalism for ergodicity loss
Author/Authors :
G.P Johari، نويسنده ,
Issue Information :
دوهفته نامه با شماره پیاپی سال 2011
Pages :
8
From page :
97
To page :
104
Abstract :
In support of the view that entropy is lost on glass formation, the image relaxation spectra were regarded as experimental proof of time- and temperature-dependent loss of both ergodicity and entropy, and confirmation of isothermal glass transition. Also, both Cp → 0 and S → 0 in the limits of tobs → 0 s, and T → 0 K were cited as further proof. We found no experimental evidence in support of the view. A critical examination shows that the image and image spectra used to reach these conclusions indicate phase-lag between the response and perturbation, not loss of ergodicity or loss of configurational degrees of freedom, and Cp → 0 as T → 0 K is not evidence for S → 0 as T → 0 K. The notions of partial ergodicity and entropy and their dependence on tobs are inconsistent with the properties measured during cooling, heating and isothermal annealing, and thermodynamic consequences of the apparent proof are untenable. The premise that glass formation is a process of continuously breaking ergodicity with entropy loss does not merit serious consideration.
Keywords :
Specific heat relaxation , Entropy , Ergodicity , Modulated calorimetry
Journal title :
Thermochimica Acta
Serial Year :
2011
Journal title :
Thermochimica Acta
Record number :
1202039
Link To Document :
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