Primary processes in spironaphtopyran (SNP), spironaphtoaxazine (SNO) and spirophenantrooxazine (SPO) after excitation by the femtosecond light pulse with the carrier wavelength 308 nm were studied by the absorption 'pump-probe' method with femtosecond time resolution. Probing was performed by means of the super-continuum light pulse with the carrier wavelength in the range 420-580 nm. Registration of the photoinduced absorption spectra dynamics allowed to observe time evolution of all intermediates. It appeared that photoinduced transformation of all three compounds has the same mechanism. Kinetic scheme is suggested and all rate constants entering this scheme are determined.