Abstract
We have examined thermal and optical properties of BaO-TiO2-GeO2 (BTG) glass in which fresnoite crystallites were precipitated after heat-treatment. We focused on the correlation between crystallization behavior and ΔTbulk-ΔTpowder value, where ΔTbulk and ΔTpowder indicate ΔT (Tx-Tg) of bulk sample and ΔT of powdered, respectively. The obtained results showed that surface crystallization and transparency of the crystallized glass were strongly correlated with the ΔTbulk-ΔTpowder value. Both refractive index and wavelength dispersion was dominated by an amount of TiO2 in the glass. These results are useful to design the BTG optical devices with high optical nonlinearity.
