الفهرس | Only 14 pages are availabe for public view |
Abstract This study presents an investigation of tellurite glasses and starts with the binary and ternary undoped tellurite glasses to study the effect of the modifier on tellurite network. Then to investigate how the structural changes affect the spectroscopic properties of rare earth ions incorporated in the glass network aiming for possible application as WLEDs. A detailed study about physical, structural, thermal and optical properties of binary magnesium tellurite ( xMgO-(100-x)TeO2), x= 10, 15, 20......45 mol% of MgO), binary borotellurite (xB2O3-(100-x) TeO2, x=10, 20, 30 mol%) and ternary magnesium borotellurite (70TeO2 - (30-x)B2O3 - xMgO, x= 5, 10, 15,....25 mol%) glasses, were introduced. The glasses were prepared in Pt-crucible by melt quenching. The density of the doped glasses takes the same behaviour of the undoped glasses but a little bit higher because of the high molecular weight of the RE ions. The structural investigations of binary magnesium tellurite glasses confirmed the conversion of TeO4 to TeO3 units and this conversion rate increases faster at MgO ≥ 30 mol%. And at MgO ˃ 45mol% no glass could be obtained due to the formation of more isolated structural units. These structural changes suggest that one group of TeO4 connected to 2 groups of TeO3 structural units needs to stabilize the glass. |