You might want to pay for this abstract it will also give you a clue to how the O-H C-H problem is tightened.
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Clip from abstract:
As with UV induced densification, polymerization of the methacrylate groups by photoinitiation with visible light triggers further polycondensation reactions between unconverted$EQV@Si-OCH$-3$/ and $EQV@Si-OH to tighten the glass matrix.
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So it appears that UV light may be part of your answer also.
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Full CLIP:
Paper #: 3469-12
Light-induced densification and mechanisms in hybrid sol-gel
glasses for photonic devices, pp.79-87
Author(s): Mark P. Andrews, McGill Univ., Montreal, QC, Canada;
K.Saravanamuttu, McGill Univ., Montreal, QC, Canada;
S. Iraj Najafi, Ecole Polytechnique de Montreal,
Saint-Laurent, QC, Canada.
Abstract: We give an account of the use of in situ waveguide
Raman spectroscopy to provide vibrational information
about structural changes that occur when a hybrid
organically modified silicate glass is irradiated with
UV or visible photons. The method is useful for
'reading' what transpires in an optical waveguide
device as it is being formed by photoinscription
methods. We describe a novel method for photoinscribing
a circular (d equals 10 micrometer) optical fiber core
on a SiO$-2$/-coated Si wafer. This is achieved by
photolysis of a visible light photoinitiator in a slab
waveguide while a standing wave is established in the
film with the 514.5 nm TE$-0$/ mode of an argon ion
laser. Simultaneous waveguide Raman spectroscopy (WRS)
gave insight into structural changes in the matrix that
ensue when the matrix is irradiated. As with UV induced
densification, polymerization of the methacrylate
groups by photoinitiation with visible light triggers
further polycondensation reactions between unconverted
$EQV@Si-OCH$-3$/ and $EQV@Si-OH to tighten the glass
matrix. |
