Infrared and Raman spectra of lead fluorosilicate glasses

Abstract The Raman (10–1200 cm −1 ) and infrared (90–2000 cm −1 ) spectra are reported for a series of lead fluorosilicate glasses having the composition (65− x )PbO− x PbF 2 −35SiO 2 , where x = 0, 10, 15, 20, and 25. The PbO band near 140 cm −1 in the Raman spectrum decreases in intensity with increasing PbF 2 content. A new band appears in the Raman spectrum near 100 cm −1 and increases in intensity as PbF 2 is added. In the far-infrared spectra, bands attributed to SiO bending motions increase in frequency and decrease in width with increasing PbF 2 content. These changes are explained as a result of the perturbation of the silicate structure by the presence of PbF 2 and by the substitution of a fluorine for an oxygen atom in the PbO 4 pyramidal units.