Tellurite And Fluorotellurite Glasses For Active And Passive

7. Surface properties; MDO 291
of glass MOD009 (77TeO2-12ZnO-10Na2O-1Yb2O3 mol. %) immersed in a 1M solution
of NaOH at 21°C.
Wt. loss / %
2.2
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0.0
y=0.01168x
R 2 = 0.97607
0 20 40 60 80 100 120 140 160 180
Time / sec.
Fig. (7.24): Etch rate of glass MOD009 (77TeO2-12ZnO-10Na2O-1Yb2O3 mol. %)
immersed in a 1M solution of NaOH at 21°C.
The glass appeared to exhibit a linear etch rate (correlation coefficient ≈ 0.976), of
around 0.012 wt. % per second.
Fig. (7.25) shows optical micrographs of glass MOD012 (75TeO2-10ZnO-10Na2O-
5GeO2 mol. %), after 60, 120, 180, and 240 sec. immersion in a 3M solution of H2SO4 at
15°C (see section 7.1.2.1 for further experimental details).