Vibrational spectroscopy of LaBSiO5 glass and glass-crystal composites

Infrared (IR) reflectivity and Raman scattering spectra of LaBSiO5 glass an d glass-crystal composites were studied in the temperature range 25-260 deg reesC. Using an analogy with the LaBGeO5 crystal it wits possible to assign the main spectral features of the LaBSiO5 glass and glass-crystal composit es. The BO4 chain arrangement and the bending vibrations Of SiO4 are influe nced by the loss of the long-range order in the glass whereas the stretchin g vibrations of the SiO4 groups are practically unaffected. The structural disorder in LaBSiO5 crystallites is caused by rotation of BO4 tetrahedra. ( C) 2001 Published by Elsevier Science B.V.