The shape of infrared spectra measured by KBr pellet technique is characterized by very strong asymmetric peak with maximum at 996-1072 cm-1 medium peak at 774-786 cm-1 and strong absorbance peak at 447-466 cm-1. The maxima positions of the first and the third absorption peaks correlate linearly with the NBO/T ratio (i.e. non-bridging oxygen to tetrahedral central atom molar ratio), which depends on the presupposed value of the network-forming fraction of Ti atomsa4(Ti). The correlation coefficient reaches maximal value for a4(Ti)=0.15 for the first peak and for a4(Ti)=0.25 for the third peak, confirming such way the partial network-forming activity of Ti02. The spectral shape is explained by the superposition of Q4(Si02; 3-dimensional), Q3(Si2O5; sheet) and Q2(SiO3; chain) structural units. The spectra of Q4 and Q3 units obtained from measured spectra by linear regression analysis are in qualitative agreement with the results of numerical FG simulation of Furukawa et al.
