Germany Glass

BOROFLOAT® 33 introduction:
BOROFLOAT®33 is a high quality borosilicate glass with outstanding properties for a wide-range of applications.
This unique special float glass is manufactured by SCHOTT Technical Glass Solutions GmbH using the Microfloat process and the latest technology. This technology also results in a homogeneous material that has an excellent mirror-like surface, a high degree of flatness and an outstanding optical quality.

Properties

  • Its excellent transmission and its very weak fluorescence intensities,high
    transmission of ultraviolet, visible and infrared wavelengths.
  • Low thermal expansion, its high thermal shock resistance andability to withstand temperatures up to 450°C for long periods.
  • Highly resistant to attack by water, strong acids, alkalis as well as organic substances.
  • It has a lower density than soda lime float glass.
  • Its low alkali content, BOROFLOAT® 33 works as a good electric insulator.

The basic parameters of the BOROFLOAT® 33:

Technical parameters:

Chemical composition:

Density(25℃)

2.2g/cm2

Thermal expansion(ISO 7991)

3.25´10-6k-1

Light transmittance

91%

Softening point

820℃

Short time use<10h

550℃

Long time use≧10h

450℃

Refractive index
(587.6nm)

1.47140

Knoop hardness

480

Basic application of the BOROFLOAT® 33:

  • Semiconductor engineering,,MEMS,sensors,Communication equipment,CCD/CMOS,
    IC package,wafer,Optical components.
  • Medical technology, biotechnology(Microarrays,slides,DNA sequencing,

    Lab-on-chip,X-ray shields,Petridishes)

  • Environmental engineering, chemical industry (resistant linings and sight glasses for reaction vessels, microfluidic systems)
  • Optics(Cover glass for reflectors,Optical instrument,Telescope lenses,UV/Telescope mirror,UV/IR cut filter,Cold light mirror,Cover glass for reflectors,

Colour wheel,Dichroicfilter/mirror,Folding mirror,DWDM filter)

  • Lighting(Stage lights,Lamp,protective panels for spotlights and high-power floodlights)
  • Home Appliances(Microwave doors,(Pyrolytic)Oven doors,Coverglass for deep pan fryers,Oven light covers,Baking trays,Commercial washing machines)
  • Photovoltaics (glass for solar collectors)

Specifications and thickness:

thickness(mm)

Tolerance(mm)

Standard size
(mm)

0.70

±0.07

1150´850



1.10

±0.1

1150´850



1.75

±0.2

1150´850



2.00

±0.2

1150´850



2.25

±0.2

1150´850



2.75

±0.2

1150´850



3.30

±0.2

1150´850


2300´1700

3.80

±0.2

1150´850


2300´1700

5.00

±0.2

1150´850


2300´1700

5.50

±0.2

1150´850


2300´1700

6.50

±0.2

1150´850


2300´1700

7.50

±0.3

1150´850


2300´1700

8.00

±0.3

1150´850


2300´1700

9.00

±0.3

1150´850


2300´1700

11.00

±0.3

1150´850


2300´1700

13.00

±0.3

1150´850


2300´1700

15.00

±0.3

1150´850


2300´1700

16.00

±0.5

1150´850

1700´1300


17.00

±0.5

1150´850

1700´1300


18.00

±0.5

1150´850

1700´1300


19.00

±0.5

1150´850

1700´1300


20.00

±0.7

1150´850

1700´1300


21.00

±0.7

1150´850

1700´1300


25.40

±1.0

1150´850



Remarks

Thickness:5.5-9mm
The minimum size:700´575mm
The maximum size:3000´2300mm

Panel thickness is continuously measured during production using laser thickness measuring equipment. Other nominal thicknesses and tolerances are supplied on request.

Thermal Properties:
The borosilicate glass' low thermal expansion, its high thermal shock resistance and its ability to withstand temperatures up to 450 °C for long periods make BOROFLOAT® 33 a good choice for applications which call for good temperature stability (e.g. internal panels in pyrolytic self-cleaning ovens and cover plates for high-power floodlights).

Coefficient of Linear Thermal Expansion

α (20 - 300 °C)

3.25 x 10-6 K-1(ISO 7991)

Remarks

Specific Thermal
Capacity

Cp (20 - 100°C)

0.83 KJ x (kg x K)-1

The maximum temperatures in use indicated apply only if the following RTG and RTS values are observed at the same time.

Specific Thermal
Conductivity

λ (90°C)

1.2 W x (m x K)-1

For short-term usage

δ max (< 10 h)

550°C

For long-term usage

δmax (≥ 10 h)

450°C

Resistance to Thermal Gradients (ability to withstand a specific temperature difference between the hot center and the cold edges of a panel) 
Test method: Test panels measuring approx. 20 x 20 cm2 are heated up in the center area to a specified temperature while the panel edge is maintained at a constant temperature. The RTG value is quoted as the temperature difference between the hot center of the panel and the cold edge area. Only 5 % of the test pieces are permitted to fail as a result of breakage due to thermal stress. To simulate extreme wear and tear in use the panels are abraded with SIC 40 grade sandpaper before the test..

RTG

1 - 100 hours

90 K

> 100 hours

80 K

Resistance to Thermal Shock (ability to withstand a sudden temperature decrease)
Test method: Test panels measuring approx. 20 x 20 cm2 are heated up in an oven and then cooled down with 50 ml of cold water (room temperature) in the center area. The RTS value is quoted as the temperature difference between the hot glass and the cold water. Only 5 % of the test pieces are permitted to fail as a result of breakage. To simulate the surface condition in practical use, the panels are treated with SIC 220 grade sandpaper before the test.


RTS for glass thickness

≤ 3.8 mm

175 K

5.0 - 5.5 mm

160 K

6.5 - 15.0 mm

150 K

> 15.0 mm

125 K

Viscosity of Borosilicate Glasses:

Working Point

104 dPas

1270 °C

Softening Point

10 7.6 dPas

820 °C

Annealing Point

10 13 dPas

560 °C

Strain Point

10 14.5 dPas

518 °C

Transformation Temperature (Tg)


525 °C

Optical Properties:
BOROFLOAT® 33 is a clear and transparent colorless borosilicate glass. The excellent transparency of BOROFLOAT® 33 both in the ultraviolet and also in the visible and near infrared range of light makes the borosilicate glass ideal as a cover panel for many types of floodlights, high-power spotlights and sunbeds (up to operating temperatures of 450 °C). Its extra low inherent fluorescence (light emission), combined with very good surface quality, flatness and homogeneity, opens up a wide-range of possible applications for BOROFLOAT® 33 in optics, opto-electronics, photonics and analytical equipment.

Wavelength λ(nm)

435.8

479.9

546.1

Index of Refraction n

1.48015

1.47676

1.47311

Wavelength λ(nm)

589.3

643.8

656.3

Index of Refraction n

1.47133

1.46953

1.46916

Abbe Constant

Ve=(ne-1)/(nF'-nC')

65.41


Refractive Index

nd(λ587.6 nm)

1.47140


Dispersion

nF-nC

71.4×10-4


Stress-optical
Coefficentin in Mpa-1

K

4.0×10-6mm2N-1MPa-1


Fluorescence Behavior of BOROFLOAT® 33

Some materials have the ability to emit electromagnetic radiation after being activated by high frequency short-wave radiation of high energy intensity. This behavior is called fluorescence. It depends on the material’s purity and its structural characteristics as well as the energy per pulse, pulse rate and the excitation wavelength of the radiation.

BOROFLOAT® 33 is a highly transparent borosilicate glass showing very weak fluorescence intensities in the visible light wavelength range.
Selected Standard Lasers and Related Wavelengths:

Wavelength
(nm)

Laser
Medium

Wavelength
(nm)

Laser
Medium

Wavelength
(nm)

Laser
Medium

308

XeCI

488

Ar

1047

Nd:YLF

325

HeCd

514.5

Ar

1053

Nd:YLF

337

N2

532

Nd:YAG

1064

Nd:YAG

350

XeF

632.8

HeNe

1153

HeNe

351.1

Ar

694.3

Ruby

1319

Nd:YAG

363.8

Ar

730-780

Alexandrite

1730

Er:YLF

427

N2

850

Er:YLF

2060

Ho:YLF

441.6

HeCd

905

GaAs

10640

CO2

Electrical Properties:

Due to its low alkali content, BOROFLOAT® 33 borosilicate glass acts as a high-power insulator. BOROFLOAT® 33 is, therefore, a suitable material for applications where good non-conductive properties at temperatures (up to 450 °C) are called for.

Because of the special structure of borosilicate glass, BOROFLOAT® 33 has a neutron absorbing effect.

Dielectric Constants
(at 25 °C and 1 MHz)

εr

(25℃,1 MHz)

4.6

Loss Tangent
(at 25 °C and 1 MHz)

tan δ

(25℃,1 MHz)

37 x 10-4

Logarithm of the Electric Volume Resistivity

lg ρ

250℃

8.0 Ω x cm

350℃

6.5 Ω x cm

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