A metal window frame might not be the best choice if you are allergic to it. Metal frames are usually made from nickel alloy. However, other metals such as copper, beryllium and aluminum can also be used. There are also titanium and gold frames. Most window frames' Neuslatten plaatsen are made of silicone, rubber, or polyvinyl chloride. Although most of these materials can trigger allergic reactions, titanium and PVC are usually hypoallergenic.