The contribution of quantum chemistry for understanding the mechanism involved in the photochromism of spirooxazines is illustrated from the calculation of three different physical properties. It is shown that the calculation of spectroscopic properties (NMR chemical shift and UV-visible absorption spectrum) and barriers of activation, the results of which are compared to the experimental data, provide a fruitful discussion basis. Confrontation of both data could lead to improve our knowledge on the complex mechanism involved in photochromism of spirooxazines.