In principle, smart glass can be applied as exterior glass. This way you can achieve privacy.
The smart glass comes in an insulating format (IGU) with a Low e layer on the outside to repel the radiation that hits the glass.
However, it is important to remember that smart glass does not become "black" but it continues to transmit the same amount of light only that the light is diffused and therefore creates a "milky" effect.
In order for glass to change between transparent and "black", or from a light transition of about 60% to a light transition of about 1%, it is necessary to apply electrochromic darkening glass, such as SAGE.