Tellurite And Fluorotellurite Glasses For Active And Passive

9. Conclusions; MDO 381
o Unidentified, possibly 1 st overtone of [TeO6] group vibration (≈ 9.3 µm ≡
1070 cm -1 ).
• The areas of the deconvoluted OH bands of the TeO2-Na2O-ZnO glasses
generally decreased in relative area, and therefore percentage OH (assuming
approximately equal extinction coefficients) by: weakly hydrogen-bonded OH >
free OH > strongly hydrogen-bonded OH.
• This difference in OH band intensities compared to silicates could be due to
charge equalisation of bridging and non-bridging oxygens.
• The multiphonon edge of the tungsten-tellurite glasses (TeO2-WO3-MO, where
MO = Bi2O3 or Nb2O5) shifted to a higher wavenumber (due to strength of W-O
bond), and developed features within the multiphonon edge with WO3 addition.
• The band at around 1770 cm -1 (5.65 µm) which grew with WO3 content was
attributed to the first overtone of the asymmetric vibrations of the [WO6]
octahedra (2 × 870 cm -1 = 1740 cm -1 ) [5, 11, 12].
• The band which occurred at around 1870 cm -1 (5.35 µm) was attributed to the first
overtone of the symmetric vibrations of the [WO4] tetrahedra (2 × 930 cm -1 =
1860 cm -1 ) [5, 11, 12].
• The relative areas of the OH bands in the tungsten-tellurite glasses did not
resemble the TeO2-Na2O-ZnO glasses, with areas in the following order: strongly
hydrogen-bonded OH > weakly hydrogen-bonded OH > free OH, signifying a
different structure.
• These overall areas of these OH bands in the tungsten-tellurite glasses were less
than the TeO2-Na2O-ZnO glasses, indicating dryer glasses.