Temperature control modes in thermal analysis*
Takeo Ozawa
Chiba Institute of Technology, Tsudanuma 275-0016,
Japan
Abstract: Now we can use several temperature control modes,
for example, isothermal run including stepwise heating and cooling,
constant rate heating (or cooling), temperature control for sample thermal
history, sample-controlled thermal analysis (SCTA or controlled-rate
thermal analysis, CRTA), temperature jump, rate jump, temperature modulation,
and repeated temperature scanning. Their advantages and drawbacks are
reviewed with some illustrative examples, especially for application
to kinetic analysis. The combined use of these varieties of temperature
control mode is recommended by showing examples. Temperature modulation
and repeated temperature scanning are discussed in comparison with temperature-modulated
differential scanning calorimetry (DSC), and common and analogous points
are elucidated. In relation to this, the possibility of the imaginary
part of the overall reaction rate constant in complex reactions is postulated.
Finally, these modes are classified and tabulated from two viewpoints,
and other possible modes are shown.
*TA Instruments-ICTA Award Lecture from the 12th
International Congress on Thermal Analysis and Calorimetry (ICTAC),
Copenhagen, Denmark, 14 18 August 2000
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