The surface tension of 0.1 Fe2O3, 15 Na2O, 11 CaO, 73.9 SiO2 glass melts (mol%) containing additions of 0.0, 0.2, 0.5 and 1.0 st% sodium sulfate were measured using pendant drop technique at temperatures between 1200-1400 deg C. Surface tension measurements were carried out in reducing (96%Ar/4%H2), inert (Argon) oxidising (Dry Air) and wet (Wet Air) atmospheres. The surface tension of the amber melts was found to decrease with increasing temperature, these increases were larger than those reported for similar glasses containing iron alone. Melt atmosphere had only a small effect on the surface tension of the sulfur containing melts at the flow rates used in this study, suggesting that sulfur decomposition could be in a sulfur-rich local environment.
