vii
TABLE OF CONTENTS
CHAPTER
1
TITLE
PAGE
DECLARATION
ii
DEDICATION
iii
ACKNOWLEDGEMENT
iv
ABSTRACT
v
ABSTRAK
vi
TABLE OF CONTENT
vii
LIST OF TABLES
x
LIST OF FIGURES
xii
LIST OF ABBREVIATIONS
xvi
LIST OF SYMBOLS
xvii
INTRODUCTION
1.1
Background of the Study
1
1.2
Statement of the Problem
4
1.3
Objective of the Study
5
1.4
Scope of the Study
5
1.5
Significance of the Study
6
1.6
Thesis Plan
7
viii
2
3
LITERATURE REVIEW
2.1
Introduction
8
2.2
Glass Formation
8
2.2.1 Non-Crystalline Structure
9
2.2.2 The Transformation Range
11
2.3
Glass Structure
12
2.4
Research Survey
12
2.5
Synthesis of Nanocrystallized Glass
18
2.5.1 Heat Treatment Process
19
2.5.2 Nucleation
20
2.5.3 Crystal Growth
20
2.6
X-Ray Diffraction
22
2.7
Thermal Analysis
25
2.8
Calculation of Activation Energy
26
2.9
Scanning Electron Microscopy
28
2.10
Density and Molar Volume
29
2.11
Photoluminescence
30
RESEARCH METHODOLOGY
3.1
Introduction
31
3.2
Sample Preparation
31
3.3
Thermal Analysis
35
3.4
Nano Glass Preparation
35
3.4.1
3.5
3.6
3.7
Heat Treatment
Identification of Nano Glass
35
36
3.5.1
X-Ray Diffraction
36
3.5.2
Scanning Electron Microscopy
37
Physical Analysis
38
3.6.1
Density measurement
38
3.6.2
Vickers Microhardness Testing
38
Photoluminescence Spectroscopy
39
ix
4
RESULTS AND DISCUSSION
4.1
Introduction
40
4.2
Glass Preparation
40
4.3
X-Ray Diffraction
42
4.4
Thermal Parameters
43
4.5
Crystallization Properties
48
4.6
4.7
4.8
5
4.5.1
X-Ray Diffraction
49
4.5.2
Scanning Electron Microscopy
50
Crystallization Kinetics
51
4.6.1
Kissinger and Ozawa Method
54
4.6.2
Activation Energy
57
4.6.3
Avrami Parameter
59
Physical Properties
62
4.7.1
Density Measurement
62
4.7.2
Vickers Microhardness Testing
66
Luminescence Spectroscopy
68
CONCLUSION
76
REFERENCES
79
Appendices
91
x
LIST OF TABLES
TABLE NO.
TITLE
PAGE
2.1
Distance between components in structure of α-TeO2
15
3.1
The nominal composition of the (80 – x) TeO2 – 5 Na2O -
32
15 MgO – (x) Eu2O3 glass system
4.1
Nominal composition of the as-prepared glass
43
4.2
DTA characteristics for Eu3+ doped tellurite glass as function of
47
dopant concentration
4.3
Crystallization peak temperature for Eu3+ doped TeO2 –
48
Na2O - MgO glass system with heat treatment process
4.4
Crystallization peak temperature for Eu3+ doped TeO2 - Na2O -
52
MgO glass system for heat treatment process
4.5
Activation energy for TeO2 - Na2O - MgO doped Eu3+ glass
57
System
4.6
Avrami exponent for TeO2 - Na2O - MgO doped Eu3+ glass
system
60
xi
4.7
Avrami exponent interpretation through the mechanism of
61
Transformation
4.8
Density and molar volume of Eu3+ doped TeO2 – Na2O –
63
MgO glass system
4.9
Density of Eu3+ doped TeO2 – Na2O – MgO heat-treated glass
64
System
4.10
Molar volume of Eu3+ doped TeO2 – Na2O – MgO heat-treated
65
glass system
4.11
The results of microhardness for Eu3+ doped TeO2 – Na2O –
67
MgO glass system
4.12
The peak wavelength, λp with corresponding transitions for
70
1mol% Eu2O3
4.13
The color region interpretation through the wavelength of
emission
72
xii
LIST OF FIGURES
FIGURE NO.
TITLE
PAGE
2.1
Crystal structure of TeO2
10
2.2
Schematic diagram for α-TeO2 structure of TeO2 unit
12
2.3
Europium atomic number from the periodic table
13
2.4
Schematic diagram of a hypothetical two-dimensional A2O3
17
oxide with AO3 triangles as structural units structure in both
crystalline and glassy forms
2.5
Model of the relationship between specific volume and
18
Temperature
2.6
Illustration of the tellurium atom coordination by oxygen
20
2.7
Dependence of growth rate on temperature
23
2.8
Bragg diffraction from a cubic crystal lattice
24
2.9 (a) Spectrum for crystalline phase
25
2.9 (b) Diffuse spectrum for amorphous phase
25
xiii
2.10
Full width half maximum for diffraction peak of [111] plane
26
2.11
A typical DTA curve for glass
27
2.12
Schematic illustration of SEM operation
30
3.1
Schematic diagram for glass preparation process
35
3.2
Glass preparation flow chart
36
3.3
X-Ray Diffractometer
38
3.4
Nanosecond Luminescence Spectroscopy System, Ekspla
44
Model NT340/1 tunabled Nd: YAG
4.1
Glass sample for 79 TeO2 - 5Na2O - 15MgO – 1 Eu2O3
43
glass composition
4.2
X-ray diffraction patterns for the (80-x) TeO2 - 5Na2O - 15MgO
44
- (x) Eu2O3 glass system
4.3
DTA patterns for TeO2 - Na2O - MgO doped Eu3+ glass system
46
4.4
The dependencies of Tg, Tc and Tm with the Eu2O3 dopant
48
concentration
4.5
The thermal stability with the Eu2O3 dopant
49
4.6
The glass forming tendency towards different Eu2O3 dopant
49
concentration
4.7
XRD spectra at room temperature for 78.5 TeO2 – 5 Na2O –
15 MgO – 1.5 Eu2O3 glass after heat-treatment at 442.7oC.
The inset shows the XRD patterns for the same glass in the
49
xiv
as-cast condition
4.8
SEM pictures obtained for heat-treated Eu2O3 (x) doped glass
50
system above Tc with (a) x = 0, (b) x = 0.5, (c) x = 1.0 and
(d) x = 2.0
4.9
DTA curves with different Eu2O3 dopant concentration, x as
52
function of different heating rates
4.10
Crystallization temperature against the dopant concentration as
53
function of different heating rate
4.11
The Kissinger plot (a) and Ozawa plot (b) for Sample 1
4.12 (a) The Kissinger plot pertaining to the crystallization
55
57
temperature, Tp as function of dopant concentration
4.12 (b) The Ozawa plot pertaining to the crystallization
58
temperature, Tp as function of dopant concentration
4.13
The activation energy of both Kissinger and Ozawa plot
61
4.14
Avrami exponent with different Eu2O3 dopant concentration
60
4.15
The dependence of density with Eu2O3 concentration for TeO2 –
63
Na2O – MgO glass system
4.16
The dependence of molar volume against Eu2O3 concentration
64
for TeO2 – Na2O – MgO glass system
4.17
A plot of hardness against Eu2O3 content for TeO2 – Na2O –
MgO for both unheat-treated and heat-treated glass system
67
xv
4.18
A luminescence spectra of Eu3+ doped TeO2 - Na2O - MgO for
68
unheat-treated glass system excited at 400 nm.
4.19
A luminescence spectra of Eu3+ doped TeO2 - Na2O - MgO
69
for heat-treated glass system excited at 400 nm.
4.20
An emission spectra of glass after doped with 1 mol% of Eu2O3
70
which is corresponding to different between untreated and
heat-treated glass.
4.21
Peak wavelength as function of concentration Eu2O3
71
4.22
Peak wavelength as function as function of transition
72
4.23
Peak intensity as function as function of different transitions
73
4.24
FWHM as function as function of transition
74
4.25
Q-1 versus transition
75
xvi
LIST OF ABBREVIATIONS
bp
-
Bipyramid
BO
-
Bridging oxygen
DTA
-
Differential Thermal Analysis
FWHM
-
Full width half maximum
g
-
gram
IR
-
Infrared
NBO
-
Non-bridging oxygen
NIR
-
Near infrared
nm
-
nanometer
PL
-
Photoluminescence
SEM
-
Scanning electron microscopy
tbp
-
Trigonal bipyramid
XRD
-
X-ray diffraction
xvii
LIST OF SYMBOLS
α
-
Crystallization fraction
b
-
Heating rate
d
-
Atomic spacing
β
-
Full width half maximum
d
-
Sample thickness
Ea
-
Activation energy
ΔE
-
Free energy difference per unit volume
∆J
-
Electric dipole
k
-
Planck’s constant
Kg
-
Glass forming tendency
m
-
Mass
M
-
Molecular weight
n
-
Avrami parameter
ρ
-
Density
ρa
-
Air density
ρl
-
Liquid density
-
Quality factor
-
Inverse quality factor
R
-
Universal gas constant
S
-
Thermal stability
∆S
-
Spin forbidden emission band
t
-
Time
T
-
Temperature
Tc
-
Crystallization temperature
Td
-
Developed temperature
Q
Q
-1
xviii
Tg
-
Glass transition temperature
Tm
-
Melting temperature
Tn
-
Nucleated temperature
U
-
Growth rate
Vm
-
Molar volume
Wa
-
Weight of sample in air
Wl
-
Weight of sample in immersion fluid
vo
-
Frequency
θ
-
Angle
λ
-
Wavelength
λ exci
-
Excitation wavelength