The IR goggles are a one-time effect. You click the button, the goggles scan once for body heat. Once a target has been picked up by the IR goggles, though, they'll remain visible to you until you end the turn and give them a chance to move. The scan will penetrate just about anything, including the outer hull of a Harvester. That's something that maybe needs to be changed in the future, perhaps by giving the IR scan the same limitations as throughwall weapons.
The glow effect doesn't do anything other than look cool so, while it probably should go away or only apply to the actors immediately in front of the guy using them, it's not too big a deal.
The range is kinda short, somewhere around 8 squares I think. The scan is cone-shaped, too. The field of view is narrower than your troops get when using the Mk1 Eyeball.