What was found
F/O WINDOW OPENED DURING TO ROLL. CREW ABORTED TAKE OFF, BRAKE TEMP LIGHT ON AFTER 80 KT ABORT, WHEELS #2 AND #3 BOXED AND SHOWING 5 ON EICAS. AIRCRAFT RETURNED TO BLOCK. AIRCRAFT WAS GROUNDED BY MAINTENANCE, MAINTENANCE INSPECTED ALL LINKAGES, DETENT AND WINDOW MECHANISM AS PER AMM 56-11-04 OPEN AND CLOSED WINDOW PER AMM 56-11-01, WINDOW IS CLOSED. LATCH AND SECURED. APPLY PRESSURE FOR DOUBLE CHECK,WINDOW REMAIN CLOSED, LATCHED AND SECURED. INSPECTED BRAKE HIGH TEMP, NO DEFECT NOTED AND NO DAMAGE ON TIRES. A/C OK FOR CONTINUE SERVICE AS PER AMM 32-41-08. AIRCRAFT RETURNED TO SERVICE.