Development and Evaluation of the Optical Properties of Optical Glass Produced from Otamiri Silica Sand

ABSTRACT

This work investigates the optical properties of glass prepared using Otamiri Silica sand mixed with analytical grade oxides as a function of their composition. Three batches were prepared with Phosphorus as the main variable of the SiO2-Na2OB2O3-CaO-ZnO glass system. The glass was melted in a ceramic crucible with a lid and the glasses melted after two hours of firing in a monolithic charcoal furnace. The effect of varying SiO2 and P2O5 on optical properties was determined using a SHIMADZU3600 spectrophotometer by determining the absorption, transmission and reflection spectra. The samples were subjected to X-ray diffraction and were confirmed to be glass from the diffuse pattern. The spectrophotometric results showed that the sample 1 glass absorbed 28% of the light and sample 2 showed peak absorption at 55% with different spectra in shape having multiple absorption centres possibly due to contamination of the glass by the crucible. The optical band gap energy was also determined from the optical band gap energy of the glass as determined by the SHIMADZU3600 spectrophotometer and found to be 2.2eV and 1.9eV for sample 1 and 2 respectively. The refractive indices of the samples were determined from the optical band gap energy of the glass as determined by the SHIMADZU3600 spectrophotometer using four different formulas and was found to range from 2.601 to 2.94 for the two samples. The refractive indices increased with increasing %P2O5 in composition in all the methods used. The refractive indices calculated using the relations all gave similar results for samples 1 and 2. Sample 3 however had a very poor chemical durability as shown by its reaction with atmospheric moisture forming a thick white crust. This was found to be due to the absence of CaO and ZnO in its composition. It is clear therefore that the glass made in this work upon further studies and research has great potential as a candidate for light scattering devices and for lighting across large surface areas.