Self-tinting Glass
Self-tinted glass or photochromic glass is a glass with special film applied on it, that influenced by UV-radiation change tint. Tint of film depends on intensity of UV-radiation. The same affect used in photochromic sunglasses.

Self-tinted glass is a perfect decision for outside glazing, as such glass regulate sun brightness by itself. Self-tinted film can be applied on existing glass.
You can buy self-tinted glass, or self-tinted films in Comboglass company in KSA.