EPR lineshape simulation studies have been performed on a specimen of 80MoO(3)-20B(2)O(3) glass in the temperature range of 300-77 K. The values of the obtained spin Hamiltonian parameters are: g(\\) = 1.940, g(perpendicular to) = 1.974, A(\\) = 150.0 x 10(-4) cm(-1), A(perpendicular to) = 35.6 x 10(-4) cm(-1) and g(\\) = 1.935, g(perpendicular to) = 1.975, A(\\) = 141.9 x 10(-4) cm(-1), A(perpendicular to) = 34.5 x 10(-4) cm(-1) at 300 and 77 K, respectively. The paramagnetic site in the specimen is molybdenyl, MoO3+, ion in which the Mo is in a distorted octahedral environment of six oxygen atoms with C-4v symmetry. The 11-parallel and 11-perpendicular line feature of the EPR lineshape shows that two Mo nuclei are magnetically equivalent in the glassy matrix, in the temperature range 300-77 K. (C) 2003 Elsevier Science B.V. All rights reserved.