Author/Authors :
R. El-Mallawany، نويسنده , , I. Abbas Ahmed، نويسنده ,
Abstract :
Quaternary tellurite glass systems of the form
80TeO2–5TiO2–(15 - x)WO3 - xAnOm where AnOm is
Nb2O5, Nd2O3, and Er2O3, x = 0.01, 1, 3, and 5 mol% for
Nb2O5 and x = 0.01, 0.1, 1, 3, 5, and 7 mol% for Nd2O3
and Er2O3, have been prepared by the melt quenching.
Density and molar volumes have been measured and calculated
for every glass system. The thermal behavior of the
glass series was studied by using the differential thermal
analysis DSC. Glass transition temperature Tg, crystallization
temperature Tc, and the onset of crystallization
temperature Tx were determined. The glass stability against
crystallization S (&100 C) and glass-forming tendency
Kg (&0.3) have been calculated. Specific heat capacity Cp
(C1.4 J/g C) was measured from room temperature and
above the Tg for every composition in each glass series.
Quantitative analysis of the above thermal properties of
these new tellurite glass with the structure parameters like
average cross-link density nc (C2.4), number of bonds per
unit volume nb (C8 9 1028 cm-3), and the average
stretching force constant (F) have been studied for every
glass composition.