Photochromic glass with sharp cutoff

• Main Authors: Araujo, Roger Jerome, Borrelli, Nicholas Francis, Seward, III, Thomas Philip, Lönnroth, Nadja Teresia, Morse, David Lathrop
• Format: Patent
• Language: English
• Published: 11.12.2018
• Subjects: CHEMICAL COMPOSITION OF GLASSES, GLAZES, OR VITREOUSENAMELS; CHEMISTRY; GLASS; JOINING GLASS TO GLASS OR OTHER MATERIALS; METALLURGY; MINERAL OR SLAG WOOL; OPTICAL ELEMENTS, SYSTEMS, OR APPARATUS; OPTICS; PHYSICS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS,MINERALS OR SLAGS; SURFACE TREATMENT OF GLASS

A photochromic glass that includes a base glass and a photochromic agent is described. The base glass is a modified boroaluminosilicate glass and the photochromic agent is a nanocrystalline cuprous halide phase. The photochromic glass exhibits a sharp cutoff in the UV or short wavelength visible portion of the spectrum along with an absorption band at longer wavelengths in the visible. The nanocrystalline cuprous halide phase includes Cu2+, which provides states within the bandgap of the cuprous halide that permit the glass to absorb visible light. Absorption of visible light drives a photochromic transition without compromising the sharp cutoff. The nanocrystalline cuprous halide phase may optionally include Ag.