Photochromic coatings containing copper bromide nanocrystals and Zn2+ Cd2+ as co activators The present dissertation investigate a photochromic glass coating made through sol gel process and dip coating route based on copper bromides crystals diffused on the glassy matrix instead of silver halides due to copperś more intense absorption of visible light. So the darkening fade process is influenced by crystal size as well as by light stimulation and heat. Furthermore the crystals should have a certain degree of disorder caused by substitution of Cu ions which will optimize the charge diffusion through the crystal i.e. the response to light stimulation (presence and absence).