Tellurite And Fluorotellurite Glasses For Active And Passive

3. Glass batching and melting; MDO 75
Fig. (3.4): Moulds used for casting glasses in this study (from left to right): large brass
(LB), small aluminium (SA) and cylindrical brass (CB).
The oxide glasses listed in table (3.1) were melted at 800°C (in a preheated furnace),
with the duration depending on the size of the batch (see table (3.5)). In general, a
larger batch weight required a longer melting time, to ensure the end glass was
completely homogeneous and all the batch materials had fully melted. The glass also
self-dried to some degree during melting, however, not to the extent of fluoride
containing glasses. The fluorotellurite glasses listed in table (3.2) were held at 800°C
for half the total melting time, and cooled to 670°C for the remainder of the melt due
to strong mould adherence if they were cast at temperatures exceeding 700°C. Again,