ABSTRACT Thermal analysis is an important technique among the established workhorses for characterization of materials. The composition changes and phase transformations of a sample as a function of temperature are important for technological application of materials, which can not be observed directly and in situ with the conventional thermal analysis techniques. Raman spectroscopy has been enthusiastically adopted by the materials community and is becoming more popular for industrial process monitoring. Recently, it was extended to thermal analysis of material in dynamic and static thermal processes to monitor the composition changes and phase transformations based on the spectra measured in a temperature interval of 1°C and named as thermo-Raman spectroscopy (TRS). Different forms of thermograms; intensity, intensity variation, band position and bandwidth as a function of temperature were also plotted to display detail information about the composition changes and phase transformations. In this review, the in situ dynamic capability of TRS in monitoring the composition changes and phase transformations is illustrated with examples. The coupling of thermogravimetric analyser (TGA) and thermo-Raman spectrometer for in situ dynamic thermal analysis with CaC2O4˙H2O as a sample exhibits consistency in end temperatures but little difference in maximum rate temperatures for the composition changes. The TRS investigations on monitoring the phase transformation of KNO3 and Na2SO4 provide important and unique information about reversibility, dynamic nature and thermal hysteresis of the phases during heating and cooling process. Thermally induced structural transformation in hydrated MoO3 and thermal decomposition of an important catalyst material (NH4) 6 Mo7 O24˙4H2O by TRS are the examples to understand the structural evolution of active phase dynamically. This shows that TRS could be useful in designing the catalyst preparation process.
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