Normal and angular transmittance measurements were performed at ENEA-Casaccia, Roma, by means of an integrating sphere, 1000 mm in diameter [1]. The cross-section diameter of the light beam incident on the sample was selected to be 60 mm, at normal

incidence, in order to cover a complete pattern for glass panes considered as samples in this paper. Taking into account the size of the samples, an entrance port of 250 mm in diameter was chosen in order to collect most of the transmitted radiation even at the highest angle of incidence considered in the measurements. For example at 30° of incidence the elliptical irradiated area of the sample had a minimum and maximum axes of 60 and 70 mm respectively. A complete set of angular measurements was also performed to get more information on the angular decay of the analysed products. The spectral measurements were performed between 350 and 800 nm and the resolution was 10 nm.

In figure 2, the spectral curves of the three selected samples are reported, to be noted how the coloured obstruction elements of sample 6 influence the spectral distribution of the transmitted light respect to the uncoloured glazing. The normal hemispherical transmittance xv of samples 6, 12, and 13, calculated using the Illuminant A as weight, are respectively: 0.679, 0.621 and 0.764. In figure 3, the angular light transmittance of the selected samples are plotted.