They will get smaller.
The pupil will have been large/wide in the dark room because your pupils automatically enlarge to take in more light when in a dark area. They correspondingly get smaller in brightly lit situations as the light-sensitive retina at the back of the eye can't cope with too much light. It has to be 'just right'!
Your pupils expand and contract because of a muscle, which is connected to the eye by the iris. When you enter a dark room the muscles will automatically expand your pupil, therefore letting it get more light. Likewise, when you enter a bright room, instead of expanding, your pupils will contract because too much light is being let in.