The Oxidation State of Sulfur on the Air Side Surface of Soda-Lime Float Glass as Determined by X-Ray Absorption near Edge Structure Spectra

Abstract

Three ways were used to prepare sulfide in soda-lime-silicate glass samples, i.e., glass heat-treated in N2/H2 (90/10 volume ratio), doped with different Carbon/Sulfur in mol ratio, as well as different sulfur source respectively. The oxidation state of sulfur on the air side surface of float glass heat-treated in N2/H2 and the bulk samples of the other two were determined by X-ray absorption near edge structure spectra (XANES). It was observed on the air side that: 1) A weak pre-edge exhibits at 2466.8eV which appears only with sulfite at high temperature and related to sulfur source; 2) A typical peak of sulfate at 2482.4eV decreases with increasing the temperature and heating duration. 3) Two peaks associated with sulfide, a broader one at about 2476.3eV and a sharper one with an accurate position at 2473.7eV. The S2- content at air side of glass heat-treated at 750 is higher than that of the glass treated at other temperatures, and increases with the heating duration, which is just the reverse at 1050, because the S2- volatilizes to the atmosphere easily at higher temperature. In addition, the content of S2- increases with increasing C/S ratio. The local environment of S2- in the glass with Na2S is different from that of with FeS, as indicated by the broader resonance. The spectra indicate that the glass heat-treated in N2/H2 (90/10), doped with different C/S ratio and with Na2S have the same sulfites or sulfites.