What material are polarized filters made from?

Polarized filters are primarily made from polyvinyl alcohol (PVA). This material is used due to its molecular structure, which allows it to be stretched and aligned in a way that enables the selective filtering of light. When PVA is processed into a polarized film, it becomes effective at blocking certain orientations of light waves, particularly glare from surfaces such as water or roads. This optical property is what makes polarized filters highly effective for various applications, including sunglasses and camera filters.

Other materials listed, such as polycarbonate, Trivex, and CR-39, are commonly used in the production of lenses but are not typically used for the fabrication of polarized filters themselves. These materials might be used as substrates or lens bases but do not possess the same light-filtering capabilities as polyvinyl alcohol when it comes to creating a polarized effect.