Glass is a poor conductor of heat, meaning it doesn't distribute warmth evenly or quickly. Windshields are made of —two layers of glass with a vinyl (PVB) interlayer. When exposed to high temperatures, the glass undergoes thermal expansion . 1. Thermal Stress
Lena leaned forward. A single crack, thin as a spider’s thread, had appeared just above the rearview mirror. It didn’t spread from an edge. It started in the middle, an ugly little star with a black center where the glass had actually fractured. can heat crack a windshield
Leaving your side windows open about half an inch allows hot air to escape, reducing the internal temperature of the cabin and the glass. Glass is a poor conductor of heat, meaning