Tellurite And Fluorotellurite Glasses For Active And Passive

7. Surface properties; MDO 323
It can be seen the model fitted the data reasonably well, although errors were potentially
large. This disparity between the data points and the fit could be due to EDX
experimental error, inhomogeneity in the glass and / or temperature of the experiment,
resulting in non-equilibrium ion-exchange, or a more complex diffusion profile (see
above). For the 100 µm side of glass T08, N0 = 0.0229 (2.3 at. %), t = 43200 seconds (i.e.
12 hours), and D = 10.58×10 -6 m 2 .s -1 (using constraint: silver fraction = 6.769×10 -3 at x =
1 µm). Fig. (7.40) shows the EDX data, and the modelling for glass T08 (80TeO2-9ZnO-
10Na2O-1Er2O3 mol. %), with 100 µm silver layer evaporated on one side, followed by
heat treatment at 285°C for 12 hours.
Fraction silver
0.035
0.030
0.025
0.020
0.015
0.010
0.005
0.000
0.0 0.2 0.4 0.6 0.8 1.0
Depth / microns
Model
EDX
Fig. (7.40): Silver concentration profile (EDX data and model) for glass T08 (80TeO2-
9ZnO-10Na2O-1Er2O3 mol. %), with 100 µm silver layer evaporated on one side,
followed by heat treatment at 285°C for 12 hours (error bars +1 at. %).