Fotokrom

Fotokrom, also known as photochrom, is a type of glass or plastic that changes color when exposed to ultraviolet (UV) light. This phenomenon is due to the presence of silver halide compounds, which are sensitive to UV radiation. When UV light hits the glass or plastic, it causes a chemical reaction that alters the structure of the silver halide, resulting in a change in color. The color change is typically reversible, meaning the material can return to its original state when exposed to visible light or heat.

Fotokromic materials are used in various applications, including sunglasses, camera lenses, and optical filters. In sunglasses, fotokromic lenses darken in response to UV light, providing protection from glare and reducing the need for manual adjustments. Camera lenses with fotokromic coatings can automatically adjust their light transmission based on the ambient light conditions, improving image quality. Optical filters with fotokromic properties can be used in scientific instruments and medical devices to control light transmission and enhance image contrast.

The color change in fotokromic materials can be customized by adjusting the composition of the silver halide compounds and the thickness of the material. This allows for the creation of a wide range of colors and shades, making fotokromic materials versatile for different applications. However, the color change is not permanent, and the material may fade over time or require periodic replacement. Additionally, the effectiveness of fotokromic materials can be affected by factors such as temperature, humidity, and the intensity of UV light.