New type of smart windows use liquid to switch from clear to reflective

https://www.nasa.gov/news/releases/latest/index.html

Researchers have demonstrated prototype windows that switch from reflective to clear with the simple addition of a liquid. The new switchable windows are easy to manufacture and could one day keep parked cars cool in the sun or make office buildings more energy efficient. The technology can also be used to make roof panels that keep houses cool in the summer and warm in the winter.
Source: Psys.org
New type of smart windows use liquid to switch from clear to reflective
Psys.org