[en] The leachability of glass has been studied by many different techniques. Most of the theoretical work has focused on only very simple glass systems. This work has lead to the identification of two main stages of glass corrosion - interdiffusion and matrix dissolution. These corrosion modes alone are inadequate to fully describe leaching of the more complicated waste glass systems. Recent work at Savannah River Laboratory (SRL) has identified a further stage of corrosion for waste glass compositions - surface layer formation. The formation and stability of protective surface layers are believed to be the most important factors affecting long-term performance of waste glass products during permanent storage. An SRL leachability model has been developed which assumes that glass corrodes congruently. The rate of corrosion is controlled by the rate of reaction of amorphous silica with water as well as the rate of diffusion of soluble silicates through the insoluble layer between the glass and the bulk solution. The thickness of the insoluble layer is proportional to the amount of glass that has dissolved from the start of the experiment. The silicate concentration gradient in the layer is equal to the difference between the silicate concentration at the glass layer interface and that in the bulk leachate divided by the layer thickness. A general equation for leaching of waste glass was derived from this model. 1 figure