Photochromic glass is a special type of glass that changes its tint in response to sunlight. When exposed to ultraviolet (UV) rays, the glass darkens, providing protection from glare and harmful UV radiation. This feature makes it popular for use in eyeglasses and sunglasses. When the light source is removed, such as when indoors, the glass gradually returns to its clear state. This ability to adapt to changing light conditions enhances comfort and visibility for users. Photochromic technology is also used in various applications, including automotive windshields and smart windows.