High barium content lead and alkaline-free glasses

• A new family of glasses free of alkaline, chemically stable has been fabricated.
• These glasses have high Barium content (54 Mol.%) and high refraction index (>1.6).
• They have been fabricated at workable melting temperature, using low cost materials.
• The obtained glasses can be considered very promising materials for optical systems.
• They are very competitive versus the ones based on expensive rare-earth.

Four glass compositions of the system BaO-Al2O3-SiO2 with high content of BaO>50% mol and with B2O3 addition (3–10 wt%) were melted at 1400 °C. The effect of alkaline earth BaO oxide on the glass phase separation and on refraction index n is investigated. IR and MAS-NMR spectroscopy are used for structural characterization. Finally stable alkaline free glasses with a content of BaO ranging from 47.4 Mol.% to 54.5 Mol.% and with a n=1.62±0.01 at 468.1 nm have been obtained.