FIELD: chemistry.
SUBSTANCE: method includes making a pellet holder with samples of the analysed glass fibres from epoxy resin and performing subsequent analysis of the samples on a scanning electron microscope, wherein samples of the analysed glass fibres are placed vertically on the pellet holder made of epoxy resin, after which the pellet holder is irradiated with X-rays and immersed simultaneously with the pellet holder containing reference samples of the glass fibres into the working chamber of the scanning electron microscope with an optical detection channel; the lateral distribution profile of germanium impurities on the cross-section of the glass fibre is then visually determined from the appearance and size of concentric annular luminescent areas with different luminescence intensity on the end surfaces of the analysed and reference glass fibres.
EFFECT: providing an express and visual method, which meets metrological requirements, for determining the lateral distribution profile of germanium impurities in the core and in boundary areas of the cladding of germanium-doped glass fibre adjacent to the core.