Abstract
The infrared spectra of Na2O-SiO2 glasses have been measured in order to study the nature of Si-O bonds in the glasses. The normal coordinate treatment has been carried out to evaluate the Si-O stretching force constant. The bond order and bond length for Si-O bonds in the glasses have been estimated by using the empirical correlations among the force constant, the bond order and the bond length. It has been found that the bond order decreases with an increase of Na2O concentration in the glasses and, as the results, the Si-O bonds are weakened. The optical absorption spectra of VO2+ ions dissolved in the glasses have been also measured in order to examine the behavior of π-electrons in Si-O-Si networks. With the spectral results, it has been confirmed that the π-electron density on the oxygen atoms in Si-O-Si networks increases with an increase of Na2O concentration in the glasses.
