incandescent

An incandescent light bulb gives off a bright glow because it's hot inside. It's usually used to describe something that's shining brightly with an inner heat.

You might hear people say "the fireworks display was incandescent" to mean it looked incredibly bright and colorful. This word can also be used to describe something that feels or looks very energetic, like a person's personality being incandescent with enthusiasm. In literature, authors might use the word incandescent to describe a moment when emotions are really intense, like when a character is overflowing with passion.