Substrate problems

Hi all -
I am trying to cure a polymer with a photosensitive crosslinker (benzophenone), which excited around 250-260 nm. The process seems to
work on silicon wafers, but doesn't on glass. The problem is that I need an optically transparent substrate with a high UV reflectivity like silicon wafers. Anyone have any ideas?
Thanks
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Hi,
Could you please elaborate further on your setup for this application - how did you place the polymer (i.e. is it sitting on a glass plate, etc) and how is the UV light source positioned with respect to the polymer?
Thanks.
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Ok, the styrenic block polymer was spin coated onto APTES coated glass or silicon wafer substrates. It is an extremely thin layer (about 20-30 nm). The UV light source has an intensity of approximately 5 mW/ cm2 at the distance from the substrates (about 1.5-2 cm) and moves back and forth on an automated moving arm that we connected to the lamp. We are doing the automation to dissipate any heat that may take the polymer above the glass transition temperature, as we considered that to be a problem due to the close proximity of the lamp to the samples. I'm mostly concerned with the surface morphology of the block copolymer, so I dip the samples in a good solvent for both blocks in order to see if it is crosslinked. On silicon, the structures remain unchanged, however, on glass this is not always the case.
Should I try to place a coating on the glass that is UV reflective (maybe sputter gold, that would bond to the APTES) or another metal maybe? Or maybe try using a UV transmissive polymer with a reflector under the substrate?
Thanks in advance for your help.
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