XIV
h
International Conference on Molecular Spectroscopy, Białka Tatrzańska 2017
198
T1: P–65
Spectroscopic studies of calcium silicate layers derived from different
organic precursors
Magdalena Rokita
1
1
AGH University of Science and Technology, Department of Material Science and Ceramics, 30-059
Kraków, al. Mickiewicza 30, Poland, e-mail: rokita@agh.edu.pl
Sol-gel method is one of prevalent methods of to produce silicate materials. Tetraethyl
orthosilicate (TEOS) is the most often used precursor of silicon in this method. Change of the silicon
precursor or replacing part of TEOS with a different precursor creates the possibility of modification
of the structure and properties of the resulting material. It may lead to change in crystallinity, as well
as change in the phase composition of the material.
A series of silicate sols including calcium was prepared by applying three types of silicon
precursors: Si(OC
2
H
5
)
4
(TEOS), (SiCH
3
)
2
(SiOC
2
H
6
)
n
(PDMS) and Si(OC
2
H
5
)
3
CH
3
(TEMS). The
received sols were heated in various temperatures in the atmosphere of argon or air. The heating time
ranged from 1 to 24 hours.
The resulting materials were subjected to the XRD PD tests to determine whether they are
crystalline or amorphic, and in case of crystalline samples to determine their phase composition. The
process of transformation and crystallisation, if any, of sols was controlled with the application of X-
ray diffraction and IR spectroscopy. As the resulting gels were very fine crystalline, considering the
high-crystalline metallic base, unanimous determination of the phase composition of the gels with the
XRD PD method was not possible. IR spectroscopy was used as the main research method. Changes
in position, shape and width of the bands depending the conditions of the heat treatment (temperature,
time and atmosphere – air or argon) as well as different types of silicon and calcium precursors were
analysed.
Fig. 1. IR spectra of selected amorphous and crystalline samples.
It was proven that silicate gels of the same assumed chemical composition may constitute one- or
multiphase material in which calcium silicates are the main phases (mostly pseudowollastonite and
tobermorite) as well as quartz or cristobalite. It was shown that the structure and phase composition of
the resulting materials are mostly determined by: atmosphere of heat treatment and the type of the
applied precursors.
Keywords: silica sol; IR spectra; Si-precursors
Acknowledgment
This work was funded under project no. 11. 11. 160. 767 at the AGH University of Science and Technology in
Krakow.
References
[1] M. Rokita, Spectrochim. Acta A 79 (2011) 733.
[2] Rokita M., Mozgawa W., Adamczyk A., J. Mol. Str. 1070 (2014) 125.
XIV
h
International Conference on Molecular Spectroscopy, Białka Tatrzańska 2017
199
T1: P–66
Optical and structural studies of tellurite glass
modified with erbium ions
Katarzyna Pach
1
, Edmund Golis
1
, Maciej Sitarz
2
, and Jacek Filipecki
1
1
Institute of Physics, Faculty of Mathematics and Natural Science, Jan Dlugosz University in
Czestochowa, Al. Armii Krajowej 13/15, 42-200 Czestochowa, Poland,
e-mail: pachkatarzyna7@gmail.com
2
Faculty of Materials Science and Ceramics, AGH University of Science and Technology,
Al. Mickiewicza 30, 30-059 Krakow, Poland
Tellurite glasses belong to a group of materials which, due to their properties, can be applied
in optoelectronics and photonics, as fast ion conductors, photonic materials and in lasers.
Tellurite glasses are treated as special glasses on account of the separately molten TeO
2
, which
does not display glass-making properties. If TeO
2
is connected with a stabilizing oxide, the
glass-making properties of the tellurite oxide are determined. Due to the fact that the tellurite
glasses are characterised by high linear as well as nonlinear index, they have become the major
research topic of nonlinear optics [1].
The objective of the study was the influence of erbium ions on the physicochemical
properties of tellurium glasses are presented. Using positron annihilation lifetime (PALS) and
Raman spectroscopy, the effect of erbium ions on the structure of tellurium glasses was
determined. Based on the lifetime values of positrons and their corresponding intensity, they can
be related to the size and quantity of structure defects such as vacancies, monovacancies,
dislocations or pores whose sizes range from a few angstroms to several dozen nanometers.
Experimental spectra of positron lifetime have two constituent lifetimes of positrons τ
1
and τ
2
.
Their interpretation was based on a binary positron capture model, where physical parameters
are annihilation velocity and rate of uptake [2]. Raman spectroscopy have allowed us to evaluate
the effect of Er
3+
ions on the structure of the material being tested [3]. On the other hand,
spectrum analysis in the Raman range allowed for assigning characteristic bands to the
appropriate functional group vibrations.
Keywords: telluric glasses; PALS; Raman; structure; erbium
References
[1] E. Golis , ES. Yousef, M. Reben, K. Kotynia, J. Filipecki, Solid State Sci. 40 (2015) 81.
[2] O. Boyko, Y. Shpotyuk, J. Filipecki, Physica Statut Solid. C 10 (2013) 121.
[3] G. E. Jellison, Thin Solid Films 33 (1998) 313.
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