Abstract
A novel type of high-temperature, high-pressure cell has been designed for near-infrared and optical spectroscopy of hydrous silicate melts at pressures up to 3 kbar and temperatures up to 800 °C. It consists of an externally heated cell with a disk-shaped sample chamber (4 mm in diameter and 0.2 mm in height) that is compressed between a tungsten carbide piston and a cylindrical sapphire window. A platinum ring surrounding the sample prevents loss of melt or water during the experiment.
The new spectroscopic cell was used for direct measurement of H2O species in alumi-nosilicate melts by near-infrared spectroscopy. Other possible applications of the cell include the study of silicate melts doped with transition metal ions in the UV-VIS-NIR and the observation of the crystallization and dissolution of minerals in hydrous silicate melts under in situ conditions.
