The Mechanics of Switchable Glass
By applying an extra-low voltage through a voltage converter the film becomes transparent. The film in the glass is opaque (almost like frosted glass) without voltage, it offers privacy but remains translucent. The secret of the film are the liquid crystals!
Both sides of the LC film are covered with a conducting layer and are connected to each other with a conductor rail. As soon as an electrical voltage passes between the two layers, the particles in between rearrange. The film turns into a transparent and sheer glass section. This switch happens within milliseconds and it can be done repeatedly since it will not wear out.