The researchers studied how a type of material called PVB behaves under stress in laminated glass. They found that PVB's ability to absorb stress changes depending on how long and how much force is applied, as well as the temperature. They used a method called the Prony-Series to understand this behavior. They discovered that PVB can only handle a certain amount of stress before it stops behaving predictably. This information helps us understand the limits of PVB's strength in real-world situations.