T.A.P. Q#382 – Is It Possible for Company to Offer Raise If I Mention I’m Leaving?

If pay is your only negative and everything else about the job is great then be upfront with your boss and have a discussion about the fact you feel you are underpaid.

Be sure you have plenty of examples of your value to the organization in terms of what you have done.If you feel this is going to be a difficult topic then invest in Susan Scott's book Fierce Conversations, plenty of excellent advice in having those hard chats.
Just my toonies worth - good luck!