succulents get their colors from a place with higher humidity or being exposed to the sun. succulents reacted the same that we do as in the sun. we get tanner but they get bright in color.

if you have a succulent at home and it used to be so bright in color but now it isn't. that's because the less exposure in light. the plant, is inside the house or more in a shaded area, would lose it's color and slowly turn back to green. you might've heard of anthocyanins and carotenoids which are pigments to the veggies and fruits you know. carotenoids gives the mainly orange,yellow and (somewhat) red hues to the apples and the autumn leaves.

but anthocyanins gives the plants red, blue and purple hues. when succulents are exposed to the Sun or extreme temperatures, their anthocyanins/ carotenoids levels increase. it acts like an antioxidants that protects the plants from overexposure from ultraviolet light. The change of color is also in their stage of protecting themselves. it is also known that anthocyanins are more stable during lower temperatures or the seasons (winter and fall). that is why the plants are more vivid in color.