We would measure vibrational spectra for Li2Si2O5 and Na2Si2O5, as well as quasielastic neutron scattering (QENS) spectra for Na2SiO5. The measurement of phonon spectra in the entire Brillouin zone over the temperature range of 300-1300 K is required for characterizing the specific phonon modes relevant to the ionic conductivity and thermal expansion behavior. The measurements would help to identify the phonons which show significant changes as a function of temperature. In addition, we propose to understand the diffusion pathways and timescales by QENS. By combining the vibrational and QENS measurements (300-1300 K) with first-principles phonon calculations and temperature-dependent molecular dynamics simulations, we expect to gain deeper insights of the origin and mechanism of ionic conductivity in amorphous phase and their relationship to phonons in these compounds.