An investigation of the optical absorption spectra of 1 mol% Pr2βO3β in mixed alkali borate glasses of the type xNa2βO.(30βx)K2βO.69B2βO3β.1Pr2βO3β (x=5, 10, 15, 20 and 25) is presented. The glasses were obtained by quenching melts consisting of Na2βCO3β,K2βCO3β,H3βBO3βandPr2βO3β(850-1000 Deg C, 1.5-2 h) between brass plates. Spectroscopic parameters like Racah (E1,E2andE3) and spin orbit ( \xi 4f) interaction parameters and Judd-Ofelt intensity parameters (\Omega 2,\Omega4 and \Omega 6) have been calculated as a function of x in the glass matrix. Radiative and nonradiative transition rates (A_T and W_M_P_R), radiative lifetimes (ΟRβ), branching ratios (\beta) and integrated absorption cross sections (\Sigma) are reported for certain excited states of Pr^3^+ in all glasses studied. Variations of these parameters as a function of composition are discussed in terms of covalency and of changes into the crystal field around the Pr^3^+ ions caused by structural changes of the glass matrix