The technology behind windows that change transparency in response to electrical voltage is known as electrochromic glazing. This innovative material is a type of smart glass that can alter its transparency, reflectivity, or color in response to an electric voltage. The electrochromic effect is typically achieved through the use of a specialized coating on the glass, which consists of multiple thin layers. The coating usually includes an electrochromic layer, an ion conductor layer, and two electrode layers. The electrochromic layer is typically made of a tungsten oxide or vanadium oxide-based material, which changes its optical properties when an electric voltage is applied. The ion conductor layer, usually made of a material like lithium lanthanum zirconium oxide, facilitates the movement of ions between the electrochromic layer and the electrode layers. When an electric voltage is applied, ions migrate between the electrochromic layer and the electrode layers, causing a change in the oxidation state of the electrochromic material. This change in oxidation state alters the material's optical properties, resulting in a change in transparency or color. The electrochromic effect can be reversed by applying a voltage of the opposite polarity, allowing the material to return to its original state.The electrochromic glazing technology has various applications, including smart windows, dynamic glazing, and adaptive building envelopes. These applications can provide benefits such as energy efficiency, reduced glare, and enhanced comfort. The technology can also be integrated with building automation systems, allowing for automated control of the glazing's transparency in response to environmental conditions like sunlight, temperature, and occupancy.