In the paper the results of ORMOSIL gels' structures' investigation were presented. As a method XRD (X-ray
diffraction) was applied. ORMOSIL gels comprising phenyl and methyl groups may be used as matrices for active layers
in optical fibre sensors because an organic dye acting as a transducer may be easily introduced into their network during
a so-called sol-gel process. Moreover, the refractive index of such layers may be modified by changing a molar ratio of
different alkoxysilanes in a sol. As a signal of an UV optical fibre sensor strongly depends on sols' composition and
ageing time it could be suggested that the structure of the gel may influence the behaviour of the dye. XRD method
enables determining positions and distances between molecules, positions of atoms, angles' and bonds' lengths between
atoms, distribution of electron's cloud's density on atoms, dipole moment of bonds and molecules as well as the nature
of bonds, therefore it may be useful in examination of the structure of partially ordered elementary cell of the gel. The
results may help to understand dependence between the structure of the gel and sensor's signal's value and lead to
achieve a better performance of the optical fibre UV sensor.
The paper concerns the results of ORMOSIL layer's applied in an optical fibre ultraviolet sensor Nuclear Magnetic
Resonance investigation. The layer which substituted for optical fibre's cladding in device's sensing part acted as a
matrix for a coumarin's derivative. The dye is able to convert ultraviolet into visible radiation which could be easily
detected. Thanks to the fact that the refractive indices of ORMOSIL layers may be controlled and reach a value
characteristic for the fused silica glass a satisfying sensitivity of the device can be achieved. However it may be expected
that both the structure and the composition of ORMOSIL matrices could influence the organic dye's behaviour. The aim
of the experiment presented in the paper was to prove a relation between the sol's condensation time and a composition
of the obtained gel's structure. The obtained NMR spectra gave the evidence of non-condensed -Si-O-C2H5(H) moieties
existence in the solid gels. Moreover, even a 42-days-long process does not lead to the total condensation of
ethoxysilanes' molecules. It is probable that the remaining ethoxy or silanol groups interact with transducer's molecules
as well as influence the refractive index of the gel layer.
The paper concerns the results of optical fibre's ultraviolet sensors' investigation. The cladding of the optical fibre's sensing part was removed and substituted with an active layer containing a coumarin's derivative designated with the number 3609. The dye acted as a transducer converting ultraviolet into visible radiation which could be easily detected. The theoretical modeling with the use of genetic algorithms proved that the best sensitivity of the sensor is achieved when the refractive indices of the active layer and the core are equal. Organically Modified Silica (ORMOSIL) matrices satisfy that condition as their refractive indices may be controlled and reach a value characteristic for the fused silica glass. However it may be expected that both the structure and the composition of ORMOSIL matrices may influence the organic dye's behaviour. The aim of the experiment presented in the paper was to measure the sensitivity of optical fibre sensors comprising the active layers composed of three alkoxysilanes which were methyltriethoxysilane (MTES), phenyltriethoxysilane (PhTES) and tetraethoxysilane (TEOS) as far as the sensitivity of the sensors with silica active layer derived from pure TEOS. Moreover, the influence of hydrolysis and condensation's time on the intensity of dye's luminescence both in active layers and sols' solutions was investigated. The results proved that hydrolysis time and gel's composition may influence a sensitivity of the sensor. Despite the initial decrease of luminescence's signal the long-lasting stability of UV/VIS conversion has been noticed which creates a possibility of the future practical application of the described sensors.
In the paper the preliminary results of the new UV-curable polymer designed for a luminophores' matrix application in the optical fibres' optical sensor investigations have been presented. The conditions of the monomer's photopolymerization, the refractive index of the obtained polymer and its mechanical properties have been examined.
In the paper the preliminary results of the investigation on the possible application of the photo-curable hybrid material
synthesis for either optical fibres' protective coatings or UV-VIS transducers' (luminophores in optical fibres' UV
sensors) matrices have been described. As the initial synthesis materials the sol-gel silica and UV-curable polyglycols'
acrylates have been used. The results of the organic-inorganic polymers' photopolymerization process investigation as
well as the properties of the obtained materials have been presented.
The paper concerns the investigation of modified silica gel materials applied in optical fibre sensors. These materials are products of a sol-gel process in which three kinds of alkoxysilanes undergo hydrolysis and condensation and may play a role of the matrices containing transducer's molecules in the active layer of the sensor. In the experiment presented below three different compositions comprising tetraethoxysilane (TEOS), methyltriethoxysilane (MTES) and phenyltriethoxysilane (PhTES) were used. The alkoxysilanes underwent hydrolysis and condensation and the obtained gels were investigated in order to determine their texture, strucuture, composition and chemical properties as far as the dependence of those characteristics on the hydrolysis time and the molar ratio of the ingredients in the initial sols. The methods employed in the experiment were: Atomic Force Microscopy (AFM) which delivered vital information about the gels' textures, contact angles' and surface charge's measurements serving to estimate chemical properties of the gels' surfaces, Nuclear Magnetic Resonance (NMR) which helped to evaluate the hydrolysis' rate and porosimetric measurements enabling a determination of BET surface area and average diametres of the pores. The results may occur important for improving the construction of optical fibre sensors in which organically modified silicates (ORMOSILs)-TEOS layes are used.
In this paper a project of a simple optical fibre ultraviolet sensor was presented. As the main part of the sensor, the
active layer containing an organic dye able to absorb ultraviolet radiation and afterwards emit radiation in a visible
range underwent the detailed investigation. The Atomic Force Microscopy (AFM) images of the gel active layers
clearly proved a relation between the surface structure, time of sol's hydrolysis and the compositions of the sols which
differed with the molar ratio of three alkoxysilanes (TEOS- tetraethoxysilane, MTES- methyltriethoxysilane and
PhTES- phenyltriethoxysilane). The experiment was being carried out during 42 days with the measurements every 7th
day. Additionaly, a dependence between the structure of the examined surface (which means also a dependence of both
remaining factors mentioned above) and emission's intensity of the sensor while excitated with a banknote-control UV
standard lamp has been noticed. The obtained results give an obvious prove the optical properties of UV optical fibres'
sensor in which a gel active layer is applied depend on many different factors, which adequately matched may result in
a big sensitivity and efficiency of such a sensor.
A new type special waveguides' production technology requires elaborating of a way of metals' introduction into the internal structure of the fibers. This study presents a way and an apparatus used for liquid phase silver layers' obtaining on the capillaries' inner surfaces, which are an integral part of waveguides, as a result of a redox process. The preliminary results of the research over silver layers' preparation reveal that the process is rather heterogeneous and the obtained layers of a few μm thickness and are porous.
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