Try to use Pirahna or O2 plasma to clean your glass and bake 150 C for 10 min to
evaporate the water vapor.
And coating Omnicoat to be the adhesion layer and coating a thin layer of
SU8-2002. After that coating your feather layer (SU-8 2025).
SU-8-SU-8 bonding is pretty good.

Lung-hao Hu