The material I use(Mucohard from parkell), a cartridge based autopolymerizing resin, reaches a "semi rigid" state in about 3 1/2 minutes after dispensing, at which time you remove it from the patients mouth and then let it finish curing for another 5 or so minutes. Trim + polish and done.
Basically during the initial 3 1/2 minute set, I'm alternating between border molding motions and having the patient close into their "regular" denture centric occlusion position to ensure that I have captured both the tissue anatomical features AND the occlussal relationship that the patient is used to.
Their are other chairside reline materials out there, that while they'll get you the same finish result, some of them are simple powder/liquid autopolymerizing acrylics and other are ligth cured acrylics. What you'll typically find once your out of d-school and if your doing some relines in your office, that you'll end up trying a couple of the different types of chairside acrylics and eventually settle on one that a) you like and b) is consistant clinically for you.