ABSTRACT
Glass, in the most general sense, consists of solid, noncrystalline materials. Since these materials lack a well defined melting point, they are sometimes considered liquids which are supercooled at room temperature. A theoretical or ideal, glassy siliceous surface is that which would exist upon terminating the continuous, three-dimensional network of fused silica. This would result in surface exposure of an unknown proportion of silicon atoms with dangling bonds, oxygen atoms with dangling bonds, and siloxane groups. By far the most important atmospheric ambient, relevant to the surface of glass, is water vapor. Any site on the surface of fused silica can, in principle, react chemically with a water molecule. A factor affecting the surface characteristics of glass under practical conditions is its tendency to pick up contamination consisting of large molecules of oily or greasy materials dispersed in the atmosphere.
