The two basic requirements for a sample container suitable for obtaining Raman spectra of corrosive melts are that the cell be optically transparent and inert to chemical attack by the melt. Several cell designs have been proposed in the past few years based on uv-visible spectroscopy experience. Two designs have been used for molten fluorides: a windowless cell in which the liquid level is maintained by its surface tension and a graphite cell with diamond windows to resist the attack by molten fluorides.
B. Gilbert, G. Mamantov, and G. M. Begun, "A Simple Raman Cell and Furnace Usable at Temperatures Higher than 1000° for Corrosive Melts," Appl. Spectrosc. 29, 276-278 (1975)