ABSTRACT
The liquid-glass transition occurs in a wide range of ma terials including the silicates, molecular liquids, molten salts, and polymers. At temperatures well below the glass transi tion temperature Tg, glasses are amorphous solids with non zero shear modulus on any measurable time scale, while their structures exhibit no evidence of long-range order. It is generally (though not universally) believed that the glass transition is a purely kinetic transition, and that no thermo dynamic phase transition is involved.