Windows are not often something you hear mentioned when talk turns to massive new breakthroughs in automotive technology, but when it comes to saving weight, no detail is insignificant. Weight saving is an important aspect of automotive design, and is one of the few areas where those concerned about fuel economy and those interested over performance are in complete agreement. Laminated glass has always been used for automotive applications because alternatives like plastic just had too many drawbacks, especially in the long term. But glass can account for as much as 100 pounds in a vehicle’s total weight, while polycarbonate equivalents could cut this figure in half.
Polycarbonate windows are already used in quite a few race cars as a weight saving measure, but this doesn’t necessarily mean they would work in road cars. The windows don’t need to last as long in a race car, and although plastic is plenty durable, it’s keeping it from scratching or hazing that are difficult. These aren’t insurmountable problems, but they are quite costly to solve. Nonetheless, Fiat will be replacing a couple of the rear side windows in the 2014 500L with polycarbonate, and as The Detroit News reports, Ford is now looking to use plastic windows in the Transit Connect van. Windows like these can cost as much as double that of glass, but this price is expected to go down as adoption ramps up. But even the current cost is less than other popular weight saving materials like carbon fiber, and that’s good news.
There is a bit of safety issue with plastic, as it doesn’t break the same way glass does, and there is a potential for it to keep first responders from being able to get at people needing medical attention. So windshields and side windows will probably stay glass for the time being, but rear windows and sunroofs could be changing in the very near future. One last advantage of polycarbonate, which has yet to be fully explored, is that it is much easier to shape than glass, and more interesting or aerodynamic designs could be used without adding any real extra cost to manufacturing. There is even the potential for it to have a major impact on automotive design as a whole.