Reduction of OH⁻ ions in tellurite glasses using chlorine and oxygen gases

Absorption losses in tellurite glasses due to OH−ions were reduced by melting the glasses under a reactive atmosphere of Cl2+ O2gas. Incorporation of dry Cl2+ O2gas has a major influence on the reduction of OH−species, which is found to be consistent with thermochemical data. Absorption loss due to OH−ions in bulk glasses prepared from the as-received raw materials and processed under a reactive atmosphere was 1000 and 60 dB/m, respectively. Gaussian fits have been used to identify the different species of OH−attached to the structural units present in the glass. All of the OH−species (free and bonded to Te), units can be reduced by melting the starting raw materials in a reactive atmosphere of Cl2+ O2.The net reduction in OH−absorbance at 3.2 µm was 1.1 cm−1, which is equivalent to 500 ppm. OH−reduction in tellurite glasses using O2gas bubbling shows a reduction in the fundamental absorption band from 1.8 to 0.57 cm−1after 75 min.