SOME PHYSICAL-PROPERTIES OF ALKALI BORATE TUNGSTATE GLASSES CONTAINING IRON

A series of borotungstate glasses was prepared. The glass formation wa s confirmed by using X-ray diffraction measurements on the powder samp les 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 sample s caused a little shift in the IR bands toward the lower frequency. Th e iron ions may act as a glass modifier whereas the tungsten ions may act as network former. The electrical conduction increased in the pres ence of tungsten due to the hopping mechanism between the two sites of tungsten (W5+, W6+). (C) 1998 Chapman & Hall.