Glass Preparation with Marly Limestone from Lopburi

Abstract

Soda lime silicate glass samples were prepared using marly limestone collected from Lopburi as the replacement of calcium oxide. The glass compositions were consistent with (75-x) SiO₂: xCaO: 25Na₂O where x is 5, 10, 15, 20, 25 and 30 mol%. The raw materials were homogenously stirred and melted in an electrical furnace with the temperature of 1,200 °C for 3 hours. Each batch of the melted materials was poured into the mold and then placed in an annealing oven with the temperature of 600 °C for 3 hours to reduce its thermal strain. The glass samples were weighted for their density and in turn calculated molar volume. The refractive index was furthermore investigated. The results show that density and  refractive index of the glass samples decrease with the increment of marly limestone while the molar volume increases. Considering for the physical and optical properties of the prepared glass samples, marly limestone collected from local area has a potential to be raw materials for colored glass and artificial gems.