Tellurite And Fluorotellurite Glasses For Active And Passive

6. Optical properties; MDO 186
%), and MOD012 (75TeO2-10Na2O-10ZnO-5GeO2 mol. %). The background absorption,
and multiphonon edge were subtracted in each case from the spectra by fitting a curve of
⎛ A ⎞
the form y = ⎜ ⎟ + B
⎝ x ⎠
4
to the data, where A and B are constants, and x is the
wavenumber, and y the absorption coefficient. This form of equation gave a reasonable
fit to the background in each case. This equation and the peak data from deconvolution
are shown on the spectra, where xi is the position of peak i, wi the half width of peak i, Ai
the area of peak i. χ 2 (is related to the iteration calculation performed by the software)
and R 2 (is the square of the correlation coefficient) indicate the degree of fit between the
generated peaks and the data (the closer χ 2 is to 0 and R 2 to 1, the better the Gaussian fit
correlates with the data).
Absoprtion coefficient / cm -1
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
Baseline: y=[(1560/x)^4]+0.36
Chi^2 = 0.00013
R^2 = 0.99573
y0 0 ±0
xc1 2264.02163 ±0.61453
w1 240.16839 ±1.0838
A1 61.68699 ±0.34992
xc2 2884.96108 ±3.68225
w2 458.28848 ±4.45136
A2 287.01307 ±4.6227
xc3 3235.19163 ±3.29137
w3 325.73209 ±3.66825
A3 100.64908 ±4.41295
Wavelength / µm
5.5 5.0 4.5 4.0 3.5 3.0 2.5
700
2000 2500 3000 3500
0
4000
Wavenumber / cm -1
FTIR data
Gaussian fit
Strong OH (2264 cm -1 )
Weak OH (2885 cm -1 )
Free OH (3235 cm -1 )
Fig. (6.8): Gaussian deconvolution of OH bands in glass MOD006 (77TeO2-10Na2O-
10ZnO-3PbO mol. %).
600
500
400
300
200
100
Loss / dB.m -1