Stability of vertical films of molten glass due to evaporation

► Observation of a vertical film made of molten glass. ► Film lifetime increases when the temperature is larger than 1250 °C. ► Evaporation of Na2O is observed using SIMS technique. ► A lubrication model is derived taking into account the gradient of surface tension. ► An equilibrium film thickness is found when the surface tension rises over 0.5%.