I always have people asking me what type of material is used in the laminated glass for impact-resistant windows and doors. A typical laminated glass is comprised of one outboard anneal glass, an interlayer and an inboard glass. Two types of interlayers are commonly used: Polyvinyl Butyral (PVB) and SentryGlas Plus (SGP).
PVB interlayer is fabricated by Dupont under the registered brand Butacite. This interlayer helps by retaining glass shards in case of breakage. Dupont offers this interlayer in clear, translucent white and other solid tints. In Florida, the translucent white is a popular choice when privacy is desired, such as in cabana bathrooms (bathrooms leading to a backyard or pool area). This option is a nice alternative to obscure glass.
The SGP interlayer, also manufactured by DuPont, is more rigid and less likely to tear than PVB. This interlayer permits less glass deflection, a good characteristics for hurricane zones. As a result, impact windows manufacturers use SGP in their larger windows, or those windows designed for the highest wind zones.
Source: Carlos Paesano http://www.impactwindows.net/2010/03/laminated-glass-used-for-impact-windows.html