A simple and inexpensive sapphire test cell has been developed for the performance of in situ Raman spectroscopy within aqueous environments up to the conditions of 400 C and 345 bar pressure. The cell volume is approximately 11 cm3 and is held by a heating enclosure within the optical path of a Raman spectrometer. With this cell, Raman vibrational measurements have been satisfactorily performed on aqueous samples and on solid substrates within aqueous environments. The test cell and its supporting equipment are fully described, as well as the Raman data manipulation method used for the processing of high-temperature aqueous Raman measurements.
David M. Carey, Eric P. Plesko, and John O. Outwater, "Advanced in Situ Sapphire Test Cell for Raman Spectroscopy within Aqueous Environments," Appl. Spectrosc. 52, 958-962 (1998)