GENERAL CATEGORIES OF GLASS Flashcards
Most common type of glass encountered in volume measurements
Borosilicate
Composition of borosilicate
80% silica
13% boric oxide (BORON)
4% sodium oxide
2-3% Aluminum oxide
Characteristics
High degree of thermal resistance and low coefficient of thermal expansion
Borosilicate
– tendency of matter to change in shape, area, and even in volume, in response to a change in the temperature that it is subjected to
Thermal expansion
The low coefficient of thermal expansion also allows the manufacturing of these products –______ glasses – have heavy walls that will give it mechanical strength, even if it has thick or heavy walls, it will still retain reasonable heat-resistance
borosilicate
Low alkali content
Resistant to alkali corrosion
Borosilicate
Free of heavy metals
Free from Mg-lime-zinc group of elements, heavy metals, arsenic, and antimony
Borosilicate
Uses
Heating – open flame or electric heating elements
Borosilicate
It is at this point that all movement of the glass molecules has reached a point where no more strain can be introduced into the glass.
Strain point
Popular brands of borosilicate
Pyrex
Kimax
Pyrex: Strain point –
Kimax: Strain point –
515C (Henry)
513C
Silica fused to____
More expensive than borosilicate glass
quartz
High silica
Strengthened chemically rather than thermally
Alumina-silica or aluminosilicate glass
Aluminosilicate glass
With_____
aluminum oxide
Greater chemical durability and can withstand higher operating temperatures
Aluminosilicate
Compared to borosilicate,________ are more difficult to fabricate – thus it is not very common in the laboratory
aluminosilicates
When coated with an electrically conductive film,_______ glass is used as resistors for electronic circuitry
aluminosilicate
High-impact, extremely strong glass
Common use: manufacture of calibrated centrifuge glass
Centrifugal force tend to pull other glasses, thus_______ glass is utilized for centrifugation.
aluminosilicate
Popular brand/s of aluminosilicate
Corex
Characteristics;
✓ Radiation-resistant
✓ 6x stronger than borosilicate (outlast conventional glassware by 10-fold)
✓ Resist clouding and scratching better
Uses:
✓ High-precision analytical work
✓ Optical reflectors and mirrors
Not used as general type of glassware in the lab – a bit difficult to manufacture
Corex (Corning, N.Y.)
Aluminosilicate
Non-laboratory uses
Outermost layer of our phone screens
Aluminosilicate
Boron-free
AKA “soft glass”
Thermal resistant
Acid/ alkali resistant glass
Acid/ alkali resistant glass popular brand
Vycor (No. 7900)
made up of fused silica
2 in 1 characteristics – heat-resistant and chemically-inert
Unique characteristics
✓ Stable to all acids except hydrofluoric types
✓ Superior in resisting corrosion by alkali than borosilicate glass – no calibration markers
✓ Unlikely contamination by contact with solutions
✓ Relatively inert to acids and neutral salts
✓ Chlorine and acid gasses does not affect it at any temperature
Vycor
Alkali/ acid resistant glass
Acid & Alkali resistant (Vycor)
Withstand high temperature
Softening temp:
1200*C
1500*C
Withstand downshocks from this temperature to ice water
Acid/ alkali resistant
Use
Ashing and ignition techniques
Acid/ alkali resistant
Contains materials that usually impart amber to red color to the glass
Low actinic glass
Reduces the amount of light transmitted to the substance in the glassware
amber to red color
Low actinic glass
Commonly uses of low actinic glass
For light-sensitive substances:
Bilirubin
VIt. A (e.g., retinol glass)
Low actinic glass
Store control materials and reagents (e.g.,)
formalin, acetone
Soda lime also known as
Flint glass
Composition of soda lime glass
Silicon oxide plus:
Soda – sodium oxide
Lime – calcium oxide
Most inexpensive glass
Soda lime glass
Readily made into a variety of types of glassware; kitchenware (ex. Wine glass)
Soda lime glass
Has a high expansion coefficient and high degree of thermal resistance
Minerals can be leached from the glass into the stored solutions
Soda lime glass
Soda lime glass in lab
Volumetric flask
Stirring rods
Single-use pipets or test tubes
