Sunglasses that can change colour rapidly

Sunglasses that can change colour rapidly Washington: A method for creating quick-changing, variable colours in films and displays, such as sunglasses, that could lead to the next hot fashion accessory has been perfected by a University of Connecticut scientist.

The new technology also has captured the interest of the U.S. military as a way to assist soldiers who need to be able to see clearly in rapidly changing environments.

The process for creating the lenses, for which a patent is pending, also is less expensive and less wasteful to manufacturers than previous methods.

"This is the next big thing for transition lenses," said Greg Sotzing, a professor of chemistry in UConn``s College of Liberal Arts and Sciences and a member of UConn``s Polymer Program.

The typical material behind a transition lens is what``s called a photochromic film, or a sheet of polymers that change colour when light hits them. Sotzing``s new technology does things slightly differently – his electrochromic lenses are controlled by an electric current passing through them when triggered by a stimulus, such as light.

"They``re like double pane windows with a gap between them," explained Sotzing.

He and his colleagues squirt a mixture of polymers – or as he calls it, "goop" – in between the layers, creating the lens as it hardens. The mixture of polymers used in this lens, said Sotzing, creates less waste and is less expensive to produce than previous mixtures.

"The lifetime of sunglasses is usually very short," said Sotzing, who points out that people often misplace them. So by making the manufacturing less expensive, he said, commercial retailers will be able to produce more of them.

Sotzing said that the world of Hollywood could have a market for this technology. He described applications he calls "freaky," including colours that move back and forth across the glasses, evoking styles like those sported by Lady Gaga.

The findings have been published in the Journal of Materials Chemistry.