To understand the dynamics of photoinduced volume expansion (PVE) in amorph
ous chalcogenides, in situ PVE (time evolution of thickness changes during
illumination) measurements have been performed. Two distinct behaviors, tra
nsient and metastable PVE, have been observed. A strong correlation between
the changes in thickness and photocurrent is reported. (C) 1999 American I
nstitute of Physics. [S0003-6951(99)00215-6].