An investigation of the effect of heat treatment on the incorporation of iron as a network former in lithium lead borate glasses

Moessbauer spectroscopy was used to study the iron- containing borate glasses, polyalkaline borate glasses and also the effect of iron oxidation on the structure and electric properties lithium lead borate glasses. Investigation of the time effect of heat treatment on 25Li2O-10PbO-65B203 based glass with addition of Fe2O3 up to 10mol% was performed. For 1mol% iron oxide up to 3mol% at different heat treatment (10, 20, 40, 70 and 150 minutes) show quadruple doublet belongs to Fe2+ and Fe3+ as well as it become well resolved as the time of heat treatment increasing. In this case the iron enters the glass network as a modifier to form FeO6 groups and Pb ions as a network former. At higher amount up to 10 mole % Moessbauer Spectra exhibit a superposition of quadruple doublet and sextet which referable to F2O3, and there are a transition from supper paramagnetic to ferromagnetic behavior. The iron ion exists in glass sample mainly in octahedral coordination rather than in tetrahedral coordination. (author)