Chalcogenide vitreous semiconductors (ChVS) are intensively investigated nowadays as perspective materials for a broad range of technical application in such areas as optical data storage, optoelectronics, holography, etc. This is due to their unique physical and optical properties such as optical transparency in IR spectral region, chemical stability, various photoinduced phenomena and high nonlinear optical properties. These properties could be modified by doping ChVS with different elements such as Ag, Mn, Sb, Cr, etc. For instance, it was found, that As2Se3 doped with Mn changes their magnetic features from diamagnetic to ferromagnetic or antiferromagnetic, and under some conditions (concentration, temperature, magnitude of external magnetic field) ChVS reach spin glass phase [1]. In this communication we report on studying of the influence of manganese doping of arsenic selenide glasses on the structure of material by means of Raman spectroscopy. The glasses composition As2Se3, As2Se3:Mn 2 % and As2Se3:Mn 5 % were prepared by standard meltquenched technique by melting of initial components in evacuated quarts ampoules with subsequent air quenching. Raman spectra were recorded using Fourier spectrophotometer Bruker IFS-55 Equinox with FRA-106 attachment. Nd-YAG laser light at wavelength of 1.06 μm was used for excitation. Measured spectra at room temperature for As2Se3, As2Se3:Mn 2 %, As2S3:Mn 5 % are presented on fig. 1. Spectra are normalized on value of band intensity near 227 cm-1 for better comparison of characteristic peaks. As can be seen from Fig. 1, substantial structural changes are noticeable at concentration of Mn > 2 % (curve 3). Intensity of bands at 116, 136, 151, 160, 171 cm-1 attributed to homopolar As–As bonds increases. The main band at 227 cm-1 corresponds to symmetrical vibrations of AsSe3 pyramidal units. On a background of the main band 200 – 300 cm-1 one can see the band at 208 cm-1 (curve 3) which is attributed to the vibrations of As–As bonds in As4Se4 unit and 241 cm-1 which indicates the presence of As–Se bonds in As4Se3 unit. The bend at 256 cm-1 is partly associated to the vibration of Se–Se bonds and As–Se bonds in As4Se3 molecular fragments. Low intensity bands near 282 cm-1 are attributed to the vibrational mode –Se– Se– bridges between AsSe3 pyramids and As4Se4 or As4Se3 molecular units. Intensity of 469 cm-1 band, characteristic for the vibrations of Se–Se bonds is decreased with the Mn introduction [2]. Thus, the presence of the additional bands besides characteristic for the vibrations of the main structural units of As2Se3 glasses - AsSe3 pyramids and different non-stoichiometric molecular fragments which contain homopolar Se–Se and As–As bonds, wasn’t observed. The main observed effect under the introduction of manganese into As2Se3 is the change of relative concentration of the main and non-stoichiometric structural units characteristic for As2Se3 glasses.figureFig. 1. Raman spectra for vitreous As2Se3 doped with Mn