B747 Captain reports that his company's maintenance department does not replace windshields when they no longer meet the standards of the Maintenance Manual; Chapter 56-11-00.

Narrative

During cruise flight; we noticed defects in the L1 windshield which could not be seen during preflight in the darkness. They included a .25-.50 inch inner layer crack and signs of moisture ingress on the top and left edges (irregular cloudy milky delamination about .5 inches wide. I called Maintenance Control to report the problem; entered it in the Log; and explained the problem to the Maintenance Supervisor on arrival. Before my flight the next day; as is my regular practice; I checked the computer to see what corrective action had been taken. I found that maintenance had signed off the problems without adequately addressing them. In my opinion; they illegally signed off these defects; for the following reasons:1. They never addressed the inner layer crack referenced in our writeup. MM 56-11-00 states 'You must remove the windshield if you find that there are cracks in the vinyl interlayer'. Note that the corrective action copied below fails to mention any reference to the reported crack.2. The window had milky cloudy delamination along the entire left and upper edges. MM 56-11-00 'Replace the windshield if a milky white film can be seen in the delaminated area. This is a sign of moisture ingress; which can cause arcing of the heating film.' I have filed several reports describing the failure of maintenance to correctly perform in accordance with established Boeing procedures regarding cockpit windows; yet this continues to occur on a regular basis. There seems not to be any FAA oversight; and the regularity of this problem concerns me; given the recent window failure resulting in a fire and an emergency landing. Defective windows requiring mandatory replacement are being dispatched on transoceanic flights; where a window failure could be catastrophic given the scarcity of suitable alternates. Additionally; I and my crew were very disappointed in the overt lack of respect for the regulations and proper maintenance procedures. This; certainly; greatly diminishes our confidence in our maintenance department. We are also very concerned that the FAA POI seems to be missing in action on this issue.Write up: L1 windshield has .25 inch inner layer crack upper left corner. Moisture ingress top-left edges.Sign off: L1 windshield cleaned and inspected no moisture noted. Delamination found at right hand side edge. Delamination check no affect visual quality; MM 56-11-00; okay to service. Maintenance notified and kept monitor.