What are those eyeglasses that turn into sunglasses called?

[Deandre]

What are those eyeglasses that turn into sunglasses when they are in the sun called? Is there a special name for them?

[Finley]

Eyeglasses that turn into sunglasses when they are in the sun are called transition glasses or photochromic lenses. The lens material of transition eyeglasses can be made of glass, plastic, and polycarbonate. In the early time, the glass photochromic lenses have silver halides (usually silver chloride) embedded in the lenses, which cause the photochromic properties. Now the plastic photochromic lenses relay on organic photochromic molecules to react to UV rays and change the color. Both of them can turn dark when exposed to UV light and fade back to clear when they are away from UV light.

[Justice]

According to your description, it is transition eyeglasses ( also called photochromic sunglasses). The eyeglasses are made of transition lenses (also called photochromic lenses) that enables them to activate, or darken, when exposed to the sun's ultraviolet light. And the greater the intensity of UV rays, the darker the lenses become. When the UV light gone, they lenses can fade back to clear lenses immediately. And with the change of UV light conditions, the level of tint adjusts. And the UV blockages remains at 100%.