Cessna 340/340A
Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Flight Crew Last 90 Days 150; Flight Crew Total 3500; Flight Crew Type 675
Troubleshooting
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Clearance
Flight Crew Returned To Departure Airport; General Maintenance Action
Aircraft
While climbing through FL180 and shortly after verifying normal cabin altitude and pressure differential; the copilot windshield blew out. I declared an emergency and initiated an emergency descent.  I safely flew the airplane back to the departure airport. I committed no negligent activity; and if I did; it was completely unintentional.
C340 Pilot reported copilot windshield blew out resulted in safe landing.