Why Don’t Windshields Shatter?

Have you ever wondered why your windshield doesn’t shatter completely during a major collision? Although the windshield may shatter, it will stick together to prevent the sharp pieces from going airborne. This is because modern vehicles are equipped with stronger windshields that sport a plastic film.

This plastic layer holds the tiny pieces of broken glass. During a direct impact, this plastic layer flexes and holds the glass in place. So basically, the glass shatters but it’s contained in this film layer. This is the reason why windshields are also called safety glass.

The hazard of plate glass windshields

The first cars ever produced didn’t use windshields. But due to the accidents brought by rain, wind, bugs, and other outdoor elements, windshields were installed. However, the glass used here was the same type used in household windows.

But as soon as more people purchased cars and discovered the harm of plated glass, they started seeking a safer version. As you know, plated glass can shatter easily with tiny bits flying into the air. This made it likely that passengers would get cut.

Another consideration here is that in the event of a collision or forceful impact, the passenger may fly out of the windshield made from plated glass. Deaths due to flying out of the car still happen up to this day due to poor windshield quality. It even has a name: “dying with a glass necklace” since most victims would be injured by the shards, not from the impact.

The creation of safe windshields

Ford was one of the first brands to innovate their windshield technology. But it wasn’t until a French chemist unintentionally discovered the power of cellulose that the present windshield was born. Edouard Benedictus was working in his lab when he suddenly knocked a beaker off the shelf. But instead of breaking into pieces, the shattered glass was held by the solidified content of the beaker.

It turns out that the beaker was left uncleaned with a cellulose matter inside. When the material fell, it broke but the cellulose matter prevented the glass from flying in different directions.

In 1905, Benedictus sought a patent for the new glass technology. However, it took many innovations and improvements by third-party companies before the present windshield glass is created. More than two decades after Benedictus released the new glass, Ford started using stronger glass material on their cars. Soon enough, almost all automobile manufacturers were using the same windshield material.

The plastic film

The safety film used in windshields is called polyvinyl butyral. This is sandwiched between two layers of glass that can also be used on windows and rear glass areas of a vehicle. Aside from adding the plastic film layer, the glass is also heated and cooled repeatedly to make it more durable. This is the reason why windshields are fairly difficult to wreck, in case you’ve tried doing so in the past.

Ensuring that your windshield isn’t prone to shattering will dictate the safety of your driving. Always fix cracks and chips as they occur to avoid bigger problems in the future.