The isothermal kinetics of the titanium-oxo-alkoxy cluster (TOAC) growth obtained in the controlled hydrolysis-condensation reaction of Ti(OPr')(4), with H2O in n-propanol solution was investigated. Kinetic curves of the TOAC growth were measured at five different temperatures: 298, 303, 308, 313, and 318 K. It was established that the kinetic curves of the TOAC growth could be mathematically modeled by the cumulative two-parameter Weibull probability distribution function of the growth time (t) in a wide range of the degree of growth (0.05 <= DG <= 0.95). It was found that the dependencies of the shape parameter (beta) and scale parameter (eta) on temperature (T) can be described by polynomial functions. The activation energy of TOAC growth (E-a,E-DG), as well as the pre-exponential factor (ln A(DG)) for different degrees of growth, were calculated using Friedman's isoconversional method. On the basis of knowing E-a,E-DG(DG) dependence, the procedure for calculating isothermal dependence of E-a vs growth time was described. The isothermal probability distribution density functions of E-a for the TOAC growth process were calculated. It was established that the conversion kinetic curves of the TOAC growth process could be fully described by a model of the infinite number of parallel first-order growth reactions with time-varying value of the pre-exponential factor and activation energies which are distributed in accordance with a specific function of E-a.