Boron isotope enrichment is obtained by selectively exciting the ν vibrational mode with multiple-photon absorption using a TEA CO2 laser, as a result, 11BOl3 dissociates and its fragments interact with dry atmosphere. Various experimental conditions affecting the enrichment coefficient were observed. Solid and gaseous products of the irradiation were measured by infrared absorption spectroscopy and mass speotroscopy. The maximum enrichment coefficient obtained was 2.3. In an experiment of greater scale, some macroscopic measurable quantities were obtained, and the productivity was about milligrams an hour. On analysing the gaseous products evaporating from a frozen sample of the residual gas, the broadening and anomalous intensification of the 1,000 cm-1 IR band were found.