Moisture-assisted crack growth in polymer adhesive/glass interfaces wa
s measured as a function of the applied energy release rate, G, using
a four-point flexure test coupled with an inverted microscope. The spe
cimens consisted of two glass plates bonded together with an epoxy or
an epoxy-acrylate adhesive. It was found that cracks formed and grew o
n both interfaces if the glass surfaces were both smooth; however, rou
ghening the surface of one of the glass plates increased the fracture
resistance of the interface sufficiently so that crack growth occurred
only on the remaining ''smooth'' interface (top or bottom). Finite el
ement analysis was used to determine the G and psi (phase angle) appro
priate for the different crack geometries. It was found experimentally
that crack growth rates for all crack geometries depended on the appl
ied G via a power law relationship and that for a given applied G, cra
ck growth rates were sensitive the crack geometry. The results indicat
e that the primary driving force for moisture-assisted crack growth at
a polymer/glass interface is the applied G at the crack tip and that
the effect of the phase angle for the different crack geometries (13 d
egrees to 54 degrees) is negligible.