Assessment of the X-ray-induced damage to sulfur in glass by laboratory X-ray fluorescence and wet chemical analysis.

Abstract

Accurate valence state analysis of sulfur in glass is crucial because sulfur, a multivalent element, plays a pivotal role in regulating glass properties. X-ray analysis is a key technique for determining the valence state of sulfur; however, high-brightness synchrotron X-ray analysis can induce damage to sulfur in glass, reducing result reliability. Laboratory wavelength-dispersive X-ray fluorescence with a single crystal (single-crystal WD-XRF) is useful for routine analysis of average sulfur valence in glass samples; however, potential damage has not been reported. In this study, the stability of sulfur valence states in glass samples subjected to X-ray irradiation was investigated. WD-XRF measurements were conducted for up to 50 h, allowing in situ observation of sulfur damage. Wet chemical analysis was subsequently performed to verify the average sulfur valence in the irradiated areas. Two types of standard soda-lime silicate glasses, SRM 1831 (clear glass, high sulfur valence) and SGT10 (amber glass, low sulfur valence), were analyzed. Average sulfur valence remained stable in SRM 1831 but was gradually oxidized in SGT10 by X-ray irradiation. Wet chemical analyses confirmed these results, indicating that the sulfur valence change in SGT10 was actual. These analyses suggest that the oxidized layer of SGT10 was limited to the surface layer of the glass. This study highlights the importance of the conditions of WD-XRF analysis for the accurate determination of sulfur valence in glass, and the need for cross-validation with wet chemical analysis.