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 Cu.sup.2+, 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.

The present invention provides a photosensitive glass material, including the following components in percentage by weight: 65-78% of SiO2; 2-12% of R2O; 5-15% of Li2O; 3-12% of Al2O3; 1.5-10% of ZrO2; 0.01-0.6% of CeO2; 0.01-0.8% of Ag2O, wherein Li2O/ZrO2 is 1.0-7.5, and the R2O is one or two of Na2O and K2O. By reasonable component design, the photosensitive glass material of the present invention has a lower dielectric loss, and photosensitive microcrystalline glass and a photosensitive microcrystalline glass product made therefrom also have lower dielectric losses, and can reduce transmission losses of electric signals of application terminals during use.

Manufacturing glass ceramic materials comprises ceramming a glass to grow a crystalline tungsten bronze phase comprising nanoparticles having a formula M.sub.xWO.sub.3, where M includes a dopant cation, and where 0<x<1.