Thermal Decomposition of CaC2O4·H2O Studied by Thermo-Raman Spectroscopy with TGA/DTA

Abstract

The advantage of Raman spectroscopy is that it can be used to identify structure. In this work, Raman spectra of CaC2O4·H2O, a calibration standard for thermogravimetric analysis/differential thermal analysis (TGA/DTA), were taken or monitored continuously in a thermal process from 25 to 750 °C with a heating rate 4 °C min-1, similar to that in TGA/DTA. The variation in Raman spectra for three structural transformations was found to be consistent with those in TGA/DTA. Furthermore, minor changes in spectra indicated the phase transformations of CaC2O4·H2O, CaC2O4, and CaCO3. Other features of the Raman spectra, the intensities of the representative bands, the derivative variation of the band intensities, the band positions, and even the background, showed some potential for application in the thermal analysis. Both the advantages and the disadvantages of thermo-Raman spectroscopy for thermal analysis were discussed in detail.