During the climbing out of Oslo, the crew of the fly SK-4031, operated by SAS Scandinavian Airlines (Boeing 737-800, registration LN-RCN) from Oslo to Stavanger (Norway) decided to return to Oslo due to the smoke in the cockpit. For this reason the crew donned their oxygen masks. During the descent a windshield cracked. The airplane landed safely about 20 minutes later. The airline reported, that a defective windshield heating element caused an electrical odor and smoke prompting the captain to turn the windshield heating off, which in turn caused one of 17 layers of the windshield to crack. The defective heating element is being investigated.