RAMAN-STUDY OF GLASSES OF BA2TISI2O8 AND BA2TIGE2O8

Raman spectra are reported for fresnoite (Ba2Ti(Si,Ge)2O8 glasses, and comparison is made between the Raman spectra of the corresponding crystalline powders and glasses of Ba2TiSi2O8 and Ba2TiGe2O8. The Ba2TiGe2O8 glass spectra show correspondence with the Ba2TiGe2O8 crystalline Raman spectra; the upsilon(s)(G-O-Ge) mode occurs at 518 cm-1 in the glass and at 521 cm-1 in the crystalline material. Five-fold coordinated titanium is the majority species present in the Ba2TiGe2O8 glass as revealed by a strong band at 824 cm-1 in the I(parallel-to) glass spectrum. The Ba2TiSi2O8 glaSS spectra are similar to the Ba2TiSiO8 crystalline spectrum; the strongest band is found at 836 cm-1 in the I(parallel-to) glass spectrum. Through comparison with the previous Raman data of other titania silicate glasses, we conclude that the Ba2TiSi2O8 glass has a structure similar to the crystalline phase.