Noritaka TAKAZAWA

Oxidization-reduction of phospahate glasses

Kazumasa MATUSITA


�@Low melting glasses contain a large amount of toxic lead oxide. One of low melting glasses without PbO is P2O5. However, various properties of P2O5 glasses were changed by reduction. In the present study, 50P2O5-50ZnO and 50P2O5-50Na2O glasses were prepared, were measured change of various properties by reduction.

The obtained glasses were clear in Atmosphere, but reduction glasses has been changed blacking them. And glass transition temperature (Tg) and softening temperature (Tf) are increased with glucose contents. The density was not changed by reduction.

In normal electrode potential, phosphate is more reducible than ZnO and Na2O. It was considered that phosphate P4O10 reductions to P4O6. P4O10 has acro-oxide of unit cell, but P4O6 does not. Therefore, phosphate is able to change thicker molecular structure. The result is that Tg and Tf increase. And also a change of a color of glass is caused by the change of coordination numbers.