a laminated glass - plastic glazing unit suitable for aircraft is disclosed . the unit comprises a pair of sheets of rigid transparent material such as glass or different sizes and an integral interlayer of thermoplastic material having a higher coefficient of thermal expansion than the sheets of rigid transparent material . the interlayer is preponderantly plasticized polyvinyl butyral and integral therewith between at least one of said rigid sheets and said interlayer is a thin layer of polyurethane to reduce the tendency of the interlayer to pull chips from one or both of the rigid sheets when the unit is exposed to extremely low temperatures while in flight in high - flying aircraft . a continuous polyurethane layer may be provided between each rigid sheet and the polyvinyl butyral interlayer or may be provided between only the rigid sheet more likely to be damaged and the polyvinyl butyral in combination with parting material interposed between the other rigid sheet less likely to be damaged and the polyvinyl butyral at or adjacent the marginal portion where the polyvinyl butyral and the other rigid sheet are integral with one another . an adhesion promoter may be provided at an interface between the polyurethane layer and its adjacent rigid sheet .