Optical properties of soda lime silica glasses

A comprehensive set of optical constants and a partial set of bulk optical properties are listed for clear, absorbing, and low-iron glasses used for windows. The measurements extend from the near ultraviolet to the far infrared, covering the range of interest for calculating solar and thermal radiative transfer through windows. This information is also needed to calculate the properties of thin-film coatings on glass substrates. Large variations in solar absorption are observed among these glasses, whereas the far-infrared properties are almost constant for all glass types. An important quantity, the hemispherical total emissivity, is 0.837 at 20°C, as determined from reflectance data measured with an IBM Fourier-transform spectrometer. Solar properties are determined from conventional transmission and reflection measurements.