As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT RETURNED TO DEPARTURE DUE TO CAPTAINS SIDE L1 WINDOW CRACKED. AN EMERGENCY WAS DECLARED AND LANDED WITHOUT INCIDENT. THE AIRCRAFT WAS GROUNDED. MAINTENANCE CONFIRMED THE WINDOW WAS CRACKED DUE TO WINDOW HEAT SYSTEM FAILURE. REPLACED THE WINDOW IAW AMM 56-11-11, THE WINDOW HEAT CONTROLLER IAW AMM 30-41-11, AND ACCOMPLISHED A SATISFACTORY OPERATIONAL CHECK.