CL65 Captain experiences uneven spoiler deployment at 7000 feet after rapidly deploying the spoilers to slow and descend at ATC request. A sharp roll to the left occurs initially before the reluctant panel deploys.

Narrative

My last clearance from New York Approach was to maintain 250 KIAS; 7;000 FT; direct to DIALS for the Expressway Visual Approach to runway 31. As we passed north of the Verrazano Narrows bridge; approaching DIALS; I knew we were going to be high and fast; but my First Officer was unable to get a word in on the frequency. When he finally did; we were instructed to descend to 3;000 FT and slow to 180 KIAS. I essentially executed a near emergency descent (Seat Belt sign was already ON). Upon rapidly deploying the flight spoilers; and initiating the descent; the aircraft began an un-commanded roll to the left. As I was about to disengage the auto-pilot; and assume manual control; the aircraft righted itself and continued toward DIALS. My First Officer had immediately selected the Flight Control synoptic page and observed the right flight spoiler outlined in white; and pointed out to me that initially the right flight spoiler had not shown full deployment; but by the time I looked at the page the right flight spoiler was displaying full deployment. We also had a FLT SPOILERS status message displayed. I believe the QRH said that there was a loss of redundancy in the system; so we continued in and landed uneventfully. The GLD Deployed advisory message posted after touchdown. After parking and deboarding; I called Maintenance Control; and wrote up the anomaly in the logbook. Maintenance came out and successfully reset the spoiler system.