| Mechanical Properties |
| Density at 20°C (68°F): Q = 2.51 g/cm3 |
| Stress-optical coefficient: C = 3.44 · 1.02 · 10-12m2/N |
| Young's modulus: E = 72.9 kN/mm2 |
| Torsion modulus: G = 30.1 kN/mm2 |
| Poisson's ratio: µ = 0.208 |
| Knoop hardness: HK100 = 590 |
| Electrical Properties |
| Dielectric constant (1 MHz): er = 6.7 |
| Dielectric loss factor (1 MHz): tan d = 61 · 10-4 |
| Electrical resistivity for A.C. 50 cycles: |
| QD (v = 250°C (482°F) ) = 1.6 · 108 W cm |
| QD (v = 350°C (662°F) ) = 3.5 · 106 W cm |
Thermal Properties
| Viscosities & Corresponding Temperatures |
 |
|
|
|
Viscosities
Log h (d Pas)
|
Temperature
°C (°F)
|
Designation
|
|
|
|
|
|
14.5
|
529 (984)
|
Strain point
|
|
13.0
|
557 (1035)
|
Annealing point
|
|
7.6
|
736 (1357)
|
Softening point
|
Transformation temperature: Tg=557°C (1035°F)
|
| Coefficient of mean linear thermal expansion: |
| a20-300 = 7.2 · 10-6K-1 |
Chemical Properties
| Chemical Resistance Data (as measured) |
|
|
|
|
|
Medium
|
5% NaOH
|
N/50 Na2CO3
|
5% HCL
|
|
|
|
|
|
|
Temp. °C
|
95
|
95
|
95
|
|
Temp. °F
|
203
|
203
|
203
|
|
Reaction time (h)
|
6.0
|
6.0
|
24.0
|
|
Loss of weight (mg/cm3)
|
2.1
|
0.05
|
0.02
|
|
Comparable loss of weight data for AF 45 (mg/cm3)
|
2.2
|
0.11
|
5.20
|
The loss of weight is determined by a test method used by specialty glass manufactures.
Processing
Please ask for DESAG's processing capabilities (i.e.: precision cutting, edge working and coatings)
|
 |
| Optical Properties |
| Refractive indices at 20°C (68°F) |
| ne (l = 546 nm) = 1.5255 |
| nd (l = 588 nm) = 1.5230 |
| Abbe value: ne = 55 |
Available Thickness Of D-263
|
|
|
| # |
Thickness
(mm) |
Thickness
(inches) |
|
|
|
|
#0
|
0.08 – 0.12
|
0.0033 – 0.0045
|
|
#1
|
0.13 – 0.16
|
0.0051 – 0.0063
|
|
#1.5
|
0.16 – 0.19
|
0.0063 – 0.0075
|
|
#2
|
0.19 – 0.23
|
0.0074 – 0.0090
|
|
#3
|
0.28 – 0.30
|
0.0110 – 0.0126
|
|
#4
|
0.38 – 0.42
|
0.0150 – 0.0165
|
|
#5
|
0.50 – 0.60
|
0.0197 – 0.0236
|
Flatness
The flatness specifications refer to a plane surface and the respective net sizes.
|
Maximum Deviations |
|
|
|
|
|
Thickness (mm)
|
as Drawn* (mm)
|
Processed (mm)
|
|
|
|
|
|
|
#3
|
0.30
|
1.2<**
|
0.35<**
|
|
#4
|
0.40
|
1.2**
|
0.35<**
|
|
#5
|
0.55
|
0.6<**
|
0.35**
|
<**No S-waves are admissible.
**Better flatness available on request. |
|
