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SUPRAX® 8488 Borosilicate glass
MAXOS
Materials SUPRAX® 8488 Borosilicate glass

The SUPRAX® 8488 product range includes disc sight glasses, reflex and transparent level gauge glasses (also as high-pressure)

The specially developed SUPRAX® 8488 borosilicate glass used for the Maxos® sight glasses guarantees superior chemical resistance. The low expansion of the glass, combined with thermal prestressing, creates high resistance to sudden temperature changes.

Technical properties

Coefficient of expansion α 20°C / 300°C
4.1 x 10–6 K–1
Max. operating temperature
300°C / 572°F
Thermal shock resistance as per ISO 720
ΔT 230°C
Transformation temperature
545°C
Glass temperature for the viscosities
dPas (Poise)
1013.0 560°C / 1040°F
107.6 800°C / 1472°F
104.0 1210°C / 2210°F
Density at 25°C
2.3 g/cm³
Modulus of elasticity
67 x 10³ N/mm²
Poisson’s ratio μ
0.20
Thermal conductivity λ at 90°C
1.2 W/(m·K)
Refractive index nd (λ = 587.6 nm)
1.482
Photoelastic parameter K
3.2 x 10–6 mm²/N
 Chemical characteristicsHydrolytic resistance
Acid resistance
Alkali resistance
Test acc. to
DIN ISO 7201)
DIN ISO 17762)
DIN ISO 6953)
Max. abrasion acc. to DIN ISO
0.1
<100 μg Na2O
each 100 cm²
>75–175 mg
each 100 cm²
Maxos®
Max. abrasion
0.050
<60 μg Na2O
each 100 cm²
>100 mg
each 100 cm²
Maxos®
HGA 1
–
Class A2
Abrasion of Maxos® glass in aqueous phase at different temperatures as a function of the ph-value.
The homogeneous distribution of the thermal prestressing ensures increased breaking strength.

It depends on the proportion: The high amount of silicon dioxide (SiO2) and boric acid (B2O3) characterizes this type as a glass former. The proportion of boric acid influences the glass properties in a specific way: We use a proportion of only 11.5 %. This makes it more stable in comparison to glasses with an even higher boric acid content. In addition, the embedding in the structural network ensures extremely high chemical resistance.

​​1) DIN ISO 720 Test procedure with classification: Water resistance of glass grains at 121°C
​​2) DIN ISO 1776 Flame spectrometry method: Resistance to hydrochloric acid at 100°C
​​3) DIN ISO 695 Test procedure with classification: Resistance to a boiling aqueous mixed alkaline solution