Temperature-Dependent Raman Spectra and Microstructure of BariumMetaborate Crystals and Its Melts

We have measured the Raman spectra of β- and α-barium metaborate in crystal and liquid states from room temperature to 1873 K, with a semiconductor laser as the laser source, coupled with a time-resolved detection system to eliminate the dense thermal emission background when temperature was considerably high. Temperature-dependent Raman spectra can clearly indicate that the phase transformation from β- and α-barium metaborate has been completed during 1273-1300 K. Variations of different kinds of microstructure units with temperature are identified and discussed.