Composition of protective atmosphere and water resistance of soda-lime glass surface

Hydrogen content in protective atmosphere of glass molten bath was investigated for its effect on water resistance of upper- and under-surfaces of thermal polished glass. Experiments were carried out on the industrial plant for auto-glass production. Contents of molecular hydrogen were varied from 2.7 to 6 % across the whole volume within the temperature range for glass mass of 1114 to 1120° C. Glass sheets were tested for water resistance in distilled water at 100° C for 24h. Time dependences of glass leaching were obtained. Difference in water resistance values was revealed for upper and under surfaces which testified to more homogeneous structure of upper layers of glass sheet. A conclusion was made on the possibility of water resistance control through variations of hydrogen content and glass mass temperature during silicate sheet glass manufacturing.