The paper provides a comparative analysis of the ability of sheet glass produced by different companies to transmit solar radiation in different ranges: 300 -2500 nm (direct solar transmission), 300 -380 nm (ultraviolet transmission), and 380 -780 nm (light transmission). It is demonstrated that a high level of light transmission does not always ensure high ultraviolet transmission.Among critical requirements imposed on sheet glasses for construction purposes is a high level of light transmission, i.e., the visible component in the solar radiation spectrum of 380 -780 nm wavelength, although the regulatory documents do not always directly specify the light transmission coefficient, which is specified, for instance, in European standards (EN 572-1:2004, EN 572-2:2004, EN 572-4:2004. The Russian standards used to specify particular values of this coefficient. Thus, according to the standard effective up to year 2001 (GOST 111-90), the light transmission coefficient of 4 mm-thick glass of the best grades M 1 and M 2 (M1 and M2 in the current state standard) has to be at least 88% and in glasses of lower grades (M 3 -M 8 ) at least 85%. The current standard GOST 111-2001 specifies the minimum admissible values of the light transmission coefficient only with respect to glass thickness, without specifying grades (for glass 4 mm thick this coefficient is equal to 88%).Marketing data on glass necessarily include data on transmission in the visible range of the solar radiation, i.e., light (coefficient of directed light transmission). Besides, producers often indicate solar radiation transmission in a wider wavelength range: from 300 to 2500 nm, i.e., including part of the ultraviolet, the visible, and the short-range infrared spectra. In technical terminology these parameters are called light transmission and solar transmission, respectively.The transmission coefficient (quality) of glass depends on the level of the technological process and on the quality of raw materials used. The contemporary float glass production method allows for producing glass where the number of defects distorting the course of the rays and decreasing directed transmission is minimal. The leading foreign and domestic manufacturers produce glass that exceeds the standard quality requirements. For instance, 4-mm float glass produced by the Borskii Glass Works, Salavatsteklo JSC, and Saratovstroisteklo JSC actually transmits more than 90% light (which is determined not only by the advanced technology, but also by high-quality initial materials).It is known [1] that the transparency of glass to visible radiation is due to the fact that chemically pure soda-lime glass has a special structure of lattice and energy zones, in which an intense energy absorption due to electron transitions between the zones (fundamental absorption) starts in the UV range approximately with 300 -350 nm and on towards increasing quantum energywhere h is the Planck's constant, n is the electromagnetic wave frequency, and l is the wavelength, and, accordingly, toward decreasi...
