Tellurite And Fluorotellurite Glasses For Active And Passive

3. Glass batching and melting; MDO 73
melt for at least 24 hours, then rinsed with distilled water and acetone and placed in a
drying oven at 100°C for at least 1 hour prior to melting. Melting was carried out
inside a silica liner (Multilab, height = 300 mm, diameter = 80 mm, wall thickness =
2.5 mm), through which dry air (BOC, < 1ppm water), was flowed (1 l.min. -1 )
through the silica lid (Multilab, diameter = 100 mm, thickness = 3 mm), dried by
passage through an A4 molecular sieve (regenerated every 6 months by heating via an
internal heater attached to a vacuum pump). The crucible was placed in, and removed
from the furnace using a ceramic cradle (alumina, height = 31 mm, diameter 48 mm,
wall thickness = 3 mm) equipped with a platinum wire as a handle. The crucibles
were removed from the furnace using a brass hooked rod and were handled during
casting with stainless steel tweezers (Fisher). Fig. (3.2) shows the melting set-up.
Housed in
fume
cupboard
Furnace
insulation
Cradle for
crucible
Fig. (3.2): Glass melting set-up.
Dry air in
Silica lid &
liner
Melting
furnace
Brass rod for
handling cradle