The Problem of the Vitreous State
The addition of a basic oxide which reacts with it to an anhydride is accompanied by the break-up of the network structure, by a decrease in the number of covalent bonds in the system, and by an increase in electrostatic and dipole interactions. Accordingly, as the alkali content is increased, the viscosity of the system in the molten state decreases and the tendency of the system to crystallize increases. Three cases are possible: 1. The resultant salt-like polar groups remain connected to the remaining anhydride network and are randomly distributed throughout it. This system is homogeneous.