ISSN:
1572-8943
Keywords:
cooling/heating rate
;
DSC
;
fragility parameter
;
glass transition temperature
;
sorbitol-fructose
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract The glass transition temperatures of sorbitol and fructose were characterized by four points determined on DSC heating thermograms (onset, mid-point, peak and end-point), plus the limit fictive temperature. The variations of these temperature values, observed as functions of cooling and heating rates, were used to determine the fragility parameter, as defined by Angell [1] to characterize the temperature dependence of the dynamic behavior of glass-forming liquids in the temperature range above the glass transition. The apparent activation energy values, determined for the different temperatures studied, were similar for fructose and sorbitol. These values were compared to data obtained from other techniques, such as mechanical spectroscopy. The variations of the apparent activation values, observed in experiments involving cooling and heating at the same rate, slow cooling followed by rate-heating, or rate-cooling followed by fast heating, were explained by aging effects occurring during the heating step.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01992837
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