Phonons in titanium doped vitreous silica

In this paper we report the infrared and Raman studies of titanium doped silicate glasses for a number of Ti concentrations. New modes associated with the titanium groups are identified. The observed shifts and broadenings in the spectra of vitreous silica are discussed in the context of random network models. The “anomalous” decrease in density with the addition of titanium is attributed to an increase in the average intertetrahedral angle of the SiO₄ network.