Portal is a first-person puzzle game. Players must solve physical challenges by opening portals to maneuver objects, and themselves, through the enigmatic Aperture Science Laboratories.
The Swirl Portals from Portal during its development. These are from 2006.
do they glow?
I'm not sure I understand your question. The Portals do not emit their colours on the nearby geometry if that's what you mean, but they appear bright as if they are glowing.