The most important layer of smart glasses is the electrochromic layers, which are usually tungsten oxide (WO3). Three central layers of transparent conductive oxide material, usually indium tin oxide (ITO), are sandwiched. Two more layers of glass can be sandwiched to protect the five layers of material. The main function of this device is to transport lithium ions to the Electrochromatic layer along the ion-conducting layer from the ion-carrying layer. The absence of ions in the electrochromic layer will cause the optical properties to change to absorb visible light. The end result in wide area is glass. All layers are obviously transparent for visible light.

      Voltage is applied across the two transparent conductive oxide layers to thicken the glass. This voltage pushes the ions through the conductive layer from the ion-deposited layer to the electrochromic layer. By reversing the process, the voltage is inverted, the ions are reversed, and the electrochromic layer is pushed through the conductive layer to the ion storage layer. When the ions migrate from the electrochromic layer, the glass color is switched on and the glass is again transparent. The benefits of this technology are reduced heat loss due to heating and cooling, increased control of the work area, and increased productivity of the manufacturers. Unique benefit is its own strength, it does not have to be supplied to the electrical system of the building for its operation.