Some physical properties of alkali borate tungstate glasses containing iron

A series of borotungstate glasses was prepared. The glass formation was confirmed by using X-ray diffraction measurements on the powder samples then measured using Mossbauer, differential thermal analysis (DTA), infra-red (IR) and d. c. conductivity. The iron in the alkali borate tungstate glass was found in the ferric state only. The introduction of tungsten to replace 25 mol % sodium tetraborate in the glass samples caused a little shift in the IR bands toward the lower frequency. The iron ions may act as a glass modifier whereas the tungsten ions may act as network former. The electrical conduction increased in the presence of tungsten due to the hopping mechanism between the two sites of tungsten (W5+, W6+). (C) 1998 Chapman & Hall.