Tin was found in the bottom of float borosilicate glasses.To simulate the enriched amounts of SnO found on the surface of the float borosilicate glasses,a series of glasses were produced in which the stannous concentration was varied from 0.1 wt%to 9.0 wt%.while the relative concentration of other components were held constant.Infrared spectra were obtained to probe the effect of increased amounts of SnO on the structure of the glass samples.The results show that SnO plays the role of an intermediate in glasses studied.When FO/SnO>1.0,SnO takes the role of network-former.And when FO/SnO