Optical Properties of Opal Glass on the Various Contents of Chemical Composition

Abstract

Opal glass samples having different chemical compositions were synthesized and transparent glass was obtained after melting. The effects of <TEX>$TiO_2$</TEX>, <TEX>$BaF_2$</TEX>, and <TEX>$CeO_2$</TEX> content on the color of the opal glass were studied by observing images of the opal samples and analyzing the results via ultraviolet visible spectroscopy and color spectrometry. The aesthetic properties of the opal glass were determined by studying the transmittance of visible light in the 400 nm to 700 nm range. The basic chemical composition of opal glass was <TEX>$SiO_2$</TEX> 52.9 wt%, <TEX>$Al_2O_3$</TEX> 12.35 wt%, <TEX>$Na_2CO_3$</TEX> 15.08 wt%, <TEX>$K_2CO_3$</TEX> 10.35 wt%, <TEX>$Ca_3(PO)_4$</TEX> 4.41 wt%, <TEX>$MgCO_3$</TEX> 1.844 wt%, <TEX>$LiCO_3$</TEX> 2.184 wt%, and <TEX>$TiO_2$</TEX> 0.882 wt%. The glass samples were prepared by varying the weight percentage of <TEX>$TiO_2$</TEX>, <TEX>$BaF_2$</TEX>, and <TEX>$CeO_2$</TEX>. The transmittance of visible light was decreased from 95 % to 75 % in the glass samples in which <TEX>$TiO_2$</TEX> content was increased from 0 to 3.882 wt%. In the blue spectrum region, as the content of <TEX>$TiO_2$</TEX> increased, the reflectance value was observed to become higher. This implies that <TEX>$TiO_2$</TEX> content induces more crystal formation and has an important effect on the optical properties of the glass. The opalescence of opal samples that contained <TEX>$CeO_2$</TEX> or <TEX>$BaF_2$</TEX> is stronger than that in the samples containing <TEX>$TiO_2$</TEX>. Opal glass samples comprising <TEX>$TiO_2$</TEX> had tetragonal lattice structures; samples including <TEX>$CeO_2$</TEX> as an additive had cubic lattice structures (FCC, <TEX>$CeO_2$</TEX>).