On the Possibility to Observe a Compensation Effect around the Glass Transition Temperature

Abstract:

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Compensation has been reported for the relaxation parameters: the activation energy W and the pre-exponential factor τ0, determined from the Thermal Sampling of Thermally Stimulated Depolarization Current technique. Below the glass transition it is assumed that the relaxation time follows an Arrhenius equation. In the vicinity of glass transition temperature an experimental thermogram may be analyzed using the Vogel-Fulcher-Tamman-Hesse (VFTH) or the Williams- Landel -Ferry equation. In this article we use the VFTH relationship to study the compensation effect in the range of glass transition. For an elementary peak obtained by TS there is a relationship between the activation energy W, the temperature of the maximum current Tm, the VFTH temperature, the compensation temperature Tc and the compensation time τ c. We employ this relationship for a basic analysis of the compensation effect in the temperature range around Tg. By numerical simulations, and assuming parameters similar to those measured experimentally, we show that it is possible to observe a compensation point in some well defined conditions

Info:

Periodical:

Materials Science Forum (Volumes 514-516)

Edited by:

Paula Maria Vilarinho

Pages:

1462-1466

DOI:

10.4028/www.scientific.net/MSF.514-516.1462

Citation:

R. M. Neagu et al., "On the Possibility to Observe a Compensation Effect around the Glass Transition Temperature", Materials Science Forum, Vols. 514-516, pp. 1462-1466, 2006

Online since:

May 2006

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Price:

$35.00

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