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 Cl-2 + O-2 gas. Incorporation of dry Cl-2 + O-2 gas 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 Cl-2 + O-2. The net reduction in OH- absorbance at 3.2 mu m was 1.1 cm(-1), which is equivalent to 500 ppm. OH- reduction in tellurite glasses using O-2 gas bubbling shows a reduction in the fundamental absorption band from 1.8 to 0.57 cm(-1) after 75 min.