Development of green light filters based on high-resistance oxide glasses colored by transition elements

Glasses in the system Al2O3–P2O5 –SiO2, which are suitable for the green light filters in traffic signal lights, were investigated. The glasses were required to satisfy the following requirements: transmission band maximum at λmax = 500 nm high heat-resistance, and low CLTE — (41 – 49) × 10–7 K–1. Transition elements served as colorants; they were introduced into the batch as the oxides TiO2, V2O5, CuO, and MoO3 in amounts 1 wt.%, as well as their pairs in different combinations. The EPR and optical spectra were investigated. It was shown that glass with the composition (wt.%) 55 P2O5, 17.1 Al2O3, 20 SiO2, 1.5 La2O3, 2 ZrO2, 2.5 B2O3, 1.5 MoO3 , and 0.5 CuO can be recommended for use as heat-resistant green light filters.