A number of Na20-Ca0-Mg0-Si02 glasses doped with different concentrations of iron and water were studied. A simple algorithm was developed to describe absorption by water and iron in each glass and to simulate the whole assemblage of spectra for pure and iron doped silicate glasses. Only two parameters, which can be determined from experimental absorption spectra, are necessary for spectra simulation. Absorption spectra of hydroxyl groups and ferrous ions for the spectral region 2900-1000nm were determined by comparing of experimental abosption spectra of glasses melted under different conditions. A new absorption band for ferrous ions was found in the region of 2980nm. This band gives significant contribution to the abosrption coefficient in the region of the water band with maximum at 2850nm.
