This is the number one enemy of a chipped windshield. Glass expands in the heat and contracts in the cold. If you have a crack, this constant movement puts stress on the damaged area.
A tiny chip in your glass might seem like a minor annoyance, but it is actually a structural ticking time bomb. Understanding why a crack in your windshield is spreading—and how to stop it—can save you hundreds of dollars in replacement costs and keep you safe on the road. The Science Behind the Spread crack in windshield spreading
The Propagation of Windshield Cracks: A Mechanical and Material Analysis of Stress Dynamics, Environmental Catalysts, and Mitigation Strategies This is the number one enemy of a chipped windshield