Sydney, June 24: If your office feels like a greenhouse in summer then wait for a new kind of glass that lets sunlight through but blocks much of its heat, which is in the process of being developed by researchers in Australia Existing solar-control glazing is either expensive or unsatisfactory in appearance. Costly versions contain layers of ultra thin silver, which absorbs infrared. Cheaper alternatives feature infrared-absorbing pigments or dyes that get broken down by strong sunlight or scatter light, giving laminated glass a smoky haze.


According to a report in nature, Stefan Schelm and Geoff Smith of the University of Technology in Sydney have developed a cheap polymer that, laminated between glass sheets, cuts out the warming wavelengths, which are just below that of red light.


Viewed at an oblique angle, it has a slight bluish haze. Otherwise, it appears transparent, with a hint of green. The new laminate's key ingredient is a compound called lanthanum hexaboride, denoted LaB6, which absorbs near-infrared radiation.

Grains of LaB6 just 20-200 millionths of a millimetre across are dispersed in plastic sheeting that is sandwiched in glass, says the report.

When just 0.02 per cent of the film's weight is added particles, the amount of infrared transmitted drops to about 5 per cent, compared with about 70 per cent for bare plastic film. Bureau Report