The luminescent property of Pr^3+ in SrB4O7 is reported. The energy level of Pr^3+ 4f5d in SrB4O7 lies above the 1^S0 state. so under UV light excitation at 207 nm, cascade emission of Pr^3+ occurs from the 1^S0 state in SrB4O7:Pr^3+(x=0.0050) or which converts a single UV photon of high energy into two visible photons. The cascade emission observed with this oxide matrix is largely due to the weak crystal field on the cation sites. Analysis of the vibrational coupling indicates that the radiative transition from the 3^P0 state is related to the low photon frequency of the borate groups (BO4) bonded to the Sr^2+ (or Pr^3+) ions (hωmax=～1200 cm^-1). The 1^So→ 1^G4(313nm), 1^S0→1^D2(338nm) and 1^S0→1^I6(405nm) transitions are responsible for the first photon emission. The second photon emission originates from the transitions from the intermediate energy levels (3^P0 and 1^D2) to the lower energy levels [3^P0→(3^HJ, 3^FJ) and 1^D2→(3^H4, 3^H5).

Key words: STRONTIUM OXIDE, BORON OXIDE, PRASEODYMIUM, CHARACTERISTICS OF LUMINESCENCE