Tellurite And Fluorotellurite Glasses For Active And Passive

9. Conclusions; MDO 384
edge across the series, with low softening points (Tg ≈ 240°C), ∆n = 0.17 for 5 to
30 mol. % ZnF2, and decreasing OH content with ZnF2 addition.
• Therefore, this series offers enhanced potential for low loss infrared transmitting
fibres compared to the TeO2-Na2O-ZnO glasses, with a prospective core / clad
pair of glasses 65TeO2-25ZnF2-10Na2O mol. % (clad, n = 1.887), and 70TeO2-
20ZnF2-10Na2O mol. % (core, n = 1.914) giving a numerical aperture of 0.32 and
θ = 19° [7].
9.4. Surface properties (Chapter 7)
X-ray photoelectron spectroscopy (XPS)
• X-ray photoelectron spectroscopy (XPS) of the as-received and fluorinated ZnF2
powder confirmed the effectiveness of the treatment, with O1s peak decreasing
from 13.2 to 3.1 at. % after fluorination [7].
• By calculation from the O1s values, the proportion of Zn(OH)F was reduced in
the powders from 39.7 to 9.4 mol. % [7].
• These values were likely to be lower, due to the presence of molecular water,
organic contaminants, and experimental error [7].
• XPS of the cleaved surface of glass MOD015 82.5TeO2-7.5WO3-10Nb2O5 mol.
% showed two components to the O1s peaks, with increasing binding energy (and
intensity), the main peak attributed to bridging / non-bridging oxygens (BOs and