Unexpectedly large relaxation time determined by in situ high-frequency shear modulus measurements near the glass transition of bulk glassy Pd40Cu30Ni10P20

High-precision in situ isothermal measurements of 550 kHz shear modulus G of bulk glassy Pd40Cu30Ni10P20 slightly below and above the glass transition temperature have been performed. It has been found, contrary to the expectation, that the observed relaxation time exceeds by 20-45 times the Maxwell relaxation time tau(m) = eta/G calculated using independent G and shear viscosity eta data. It has been concluded that tau(m) may not serve as a universal time scale for different relaxation processes in supercooled liquid and glassy states. (C) 2010 Elsevier B.V. All rights reserved.