Characterization of polymers in the glass transition range: time-temperature and-aging time superposition in polycarbonate

Jean Jacques Pesce, Jan M. Niemiec, Martin Y. Chiang, Carol L. Schutte, Carl R. Schultheisz, Gregory B. McKenna

Research output: Contribution to journalConference articlepeer-review

3 Scopus citations


Here we present time-temperature and time-aging time superposition data for a commercial grade polycarbonate. The data reduction is performed for dynamic-mechanical data obtained in torsion over a range of temperatures from 103.6 to 144.5°C and aging times of 16 h. For time-temperature superposition the results show the deviation of the sub-Tg response from the WLF equation. Two response regimes are observed: at temperatures far below Tg the log(aT) is linear in T, followed by a transition towards the WLF behavior as Tg is approached. The temperature at which the behavior changes from a linear dependence of log(aT) on T to the transition-type behavior is found to depend on the aging time. This temperature decreases as aging time increases. The time-aging time response is found to behave in a normal way. At temperature far below Tg the log (ae) vs log(te) is constant and has a slope somewhat less than unity. However, nearer to Tg the slope decreases and there is a second regime of in which the aging virtually ceases. In this polycarbonate, above 136.9°C, no aging is observed.

Original languageEnglish
Pages (from-to)77-83
Number of pages7
JournalAmerican Society of Mechanical Engineers, Applied Mechanics Division, AMD
StatePublished - 1995
EventProceedings of the 1995 Joint ASME Applied Mechanics and Materials Summer Meeting - Los Angeles, CA, USA
Duration: Jun 28 1995Jun 30 1995


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