Elastic and mechanical properties of 10La(2)O(3).30Bi(2)O(3).60B(2)O(3) (LaBiB) glass, 15K(2)O.15Nb(2)O(5). 68TeO(2).2MoO(3) (KNbTeMo) glass and a transparent KNbTeMo nanocrystallized (particle size: similar to40 nm) glass were examined using cube resonance and nanoindentation methods. The values of Poisson's ratio, Young's modulus (E), Debye temperature (theta(D)), fractal bond connectivity, Martens hardness, indentation hardness, indentation Young's modulus, elastic recovery, Vickers hardness, fracture toughness (K-c) and brittleness for the samples were evaluated, and the relation with the structure and nanocrystallization were clarified. LaBiB glass containing high oxygen-coordinated La3+ ions and two-dimensional BO3 structural units shows excellent properties of E = 90.6 GPa, theta(D) = 404 K and K-c = 0.72 MPa m(1/2) and a high resistance against deformation during, Vickers indentation. KNbTeMo glass with the three-dimensional network structure and consisting of weak Te-O bonds has small values of E = 51.4 GPa and K-c = 0.29 MPa m(1/2). It was demonstrated that the elastic and mechanical properties of KNbTeMo precursor glass are largely improved by nanocrystallization, e.g., E = 69.7 GPa and K-c = 0.32 MPa m(1/2). The nanocrystallization also induces a high resistance against deformation during Vickers indentation. (C) 2004 Elsevier Ltd. All rights reserved.