Abstract
An attempt has been made determine the types of Al
3+ structural units in potassium alumino borate glass. Therefore a number of investigations have been carried out on the relation between the composition of the glasses and their properties. The density, refractive index, and hardness of a number of compositions in which Al
2O
3 replaces B
2O
3 at constant K
2O were measured. It appears that the replacement of B
2O
3is not entirely without some consequencies.
The concentration of non-bridging oxygen ions increases with the introduction of Al
2O
3.
Non bridging oxygen ions start aappearing at alkali concentration of about 0.2 mol K
2O.