Safety glass

Edouard Benedictus, a French scientist, was working in his laboratory. The year was 1903. Benedictus climbed a ladder to fetch reagents from a shelf and inadvertently knocked a glass flask to the floor. He heard the glass shatter, but when he glanced down, to his astonishment, the broken pieces of the flask still hung together, more or less in their original contour.

On questioning an assistant, Benedictus learned that the flask had recently held a solution of cellulose nitrate, a liquid plastic, which had evaporated, apparently depositing a thin coating of plastic on the flask’s interior. Because the flask appeared cleaned, the assistant, in haste, had not washed it but returned it directly to the shelf.

As one accident had led Benedictus to the discovery, a series of other accidents directed him toward its application. In 1903, automobile-driving was a new and often dangerous hobby among Parisians. The very week of Benedictus’s laboratory discovery, a Paris newspaper ran a feature article on the recent rash of automobile accidents. When Benedictus read that most of the drivers seriously injured had been cut by shattered glass windshields, he knew that his unique glass could save lives.

As he recorded in his diary: “Suddenly there appeared before my eyes an image of the broken flask. I leapt up, dashed to my laboratory, and concentrated on the practical possibilities of my idea.”

For twenty-four hours straight, he experimented with coating glass with liquid plastic, then shattering it. “By the following evening,” he wrote, “I had produced my first piece of Triplex (safety glass) – full of promise for the future.”

Unfortunately, automakers, struggling to keep down the price of their new luxury products, were uninterested in the costly safety glass for windshields. The prevalent attitude was that driving safety was largely in the hands of the driver, not the manufacturer. Safety measures were incorporated into automobile design to prevent an accident but not to minimise injury if an accident occurred.

It was not until the outbreak of World War I that safety glass found its first practical, wide-scale application: as lens for gas masks. Manufacturers found it relatively easy and inexpensive to fashion small ovals of laminated safety glass, and the lenses provided military personnel with the kind of protection that was desperately needed but had been impossible until that time. After automobile executives examined the proven performance of the new glass under the extreme conditions of battle, safety glass’ major application became car windshields. Today safety glass, which will not splinter when exposed to shock, is everywhere-in windshields for cars, goggles for machinists, and windows and doors for many public buildings.

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