Why Does Glass Get Moldy, and What Should Be Noted for Glass Maintenance?
In people's inherent perception, "mold" seems to be the "patent" of organic materials such as wood, food, and textiles. Glass, which is crystal - clear and hard in texture, seems to have nothing to do with "mold" at all. However, in daily life, many people have encountered situations like this: a hazy layer of white fog appears on the surface of glassware that has been stored for a long time, which is difficult to clean with clean water; dark gray spots grow on bathroom glass partitions after long - term use; even the edges of glass plates purchased not long ago show mesh - like lines. These phenomena that seem to be "cleaning problems" are actually the manifestations of glass "mold". Then, as an inorganic non - metallic material, why does glass have the "mold" problem similar to that of organic materials? How should we scientifically maintain glass in daily life to avoid damage to its performance?
1. Unveiling the Mystery of Glass "Mold": It is Not Caused by Fungi, but a Chemical Change
First of all, it is necessary to clarify that the "mold" of glass is essentially different from that of food and wood. The latter is the result of the massive reproduction of microorganisms (fungi) under suitable temperature and humidity conditions, which decompose organic substances to produce metabolites. The "mold" of glass, on the other hand, is essentially a chemical corrosion phenomenon occurring on the surface of glass, which is usually called "glass mildew" or "glass weathering" in the industry. The occurrence of this phenomenon is closely related to the composition of glass, the storage environment, and usage habits.
The main component of glass is silicon dioxide (SiO₂). In the production process, fluxes such as sodium carbonate (Na₂CO₃) and calcium carbonate (CaCO₃) are added to reduce the melting temperature and improve stability. Finally, an amorphous solid mainly composed of sodium silicate (Na₂SiO₃), calcium silicate (CaSiO₃), and silicon dioxide is formed. Among them, sodium silicate has relatively active chemical properties and is prone to react with moisture and carbon dioxide in the air - this is the core cause of glass "mold".
When glass is in a high - humidity environment (relative humidity exceeding 65%), water molecules in the air will penetrate into the micro - gaps on the surface of glass and undergo a hydrolysis reaction with sodium silicate: Na₂SiO₃ + 2H₂O → 2NaOH + H₂SiO₃. The generated sodium hydroxide (NaOH) is a strong alkaline substance, which will further corrode the silicon dioxide on the surface of glass, form new sodium silicate and water, and cause damage to the silicate skeleton structure on the surface of glass; the other product, silicic acid (H₂SiO₃), is a white colloidal substance insoluble in water, which will adhere to the surface of glass and form a hazy "mold spot". This is why moldy glass loses transparency and feels astringent.
In addition, temperature and pollutants will accelerate the mildew process of glass. When the ambient temperature is between 20 - 40℃, the activity of water molecules increases, and the rate of hydrolysis reaction will be significantly improved; if the air contains pollutants such as dust, oil, and salt (such as sea breeze in coastal areas), these substances will have a secondary reaction with the sodium hydroxide on the surface of glass, forming stubborn stains that are more difficult to remove, and even leaving permanent corrosion marks on the surface of glass. For example, bathroom glass is in a high - temperature and high - humidity environment for a long time and is easily contaminated with substances containing surfactants such as body wash and shampoo, so its mildew rate is 3 - 5 times faster than that of ordinary indoor glass.
2. Core Principles of Glass Maintenance: Isolating Causes, Timely Cleaning, and Scientific Protection
Since the "mold" of glass is the result of the combined action of chemical corrosion and environmental factors, the core of maintenance lies in "isolating the causes" - by controlling temperature and humidity, reducing contact with pollutants, and at the same time, cooperating with timely cleaning and scientific protection to delay or even avoid the occurrence of glass mildew. Specifically, the maintenance of glass in different scenarios can follow the following methods:
(1) Daily Storage: Controlling Temperature and Humidity, Avoiding Stacking and Squeezing
For glassware (such as wine glasses, bowls, and plates), glass plates, or lenses that are not in use temporarily, the control of temperature and humidity in the storage environment is crucial. First of all, a dry and well - ventilated place should be selected, and glass should not be stored in areas with long - term humidity such as basements, bathrooms, and under sinks; if the ambient humidity is high (such as the plum rain season in southern China), dehumidification bags, quicklime, or dehumidifiers can be placed in the storage space to control the relative humidity below 50%.
Secondly, direct contact and squeezing between glass should be avoided during storage. Although the surface of glass seems smooth, it actually has tiny unevenness. When stacked, the dust or impurities on the surface will form "fulcrums", leading to concentrated local pressure and the generation of fine scratches - these scratches will become "breakthroughs" for water molecules and pollutants, accelerating mildew. It is recommended to place a clean soft cloth or moisture - proof paper between each piece of glass. Especially for surface - sensitive types such as glass lenses and coated glass, they should be wrapped with a special moisture - proof protective film before storage.
In addition, it is necessary to avoid long - term contact between glass and alkaline substances (such as soap, undiluted detergent) and acidic substances (such as vinegar, lemon juice). If glass is accidentally contaminated with these substances, it should be rinsed with clean water immediately; otherwise, the protective layer on the surface of glass will be damaged, laying hidden dangers for mildew.
(2) Daily Cleaning: Choosing the Right Tools to Avoid "Secondary Damage"
Cleaning is an important link in preventing glass mildew, but incorrect cleaning methods will damage the surface of glass and accelerate mildew. First of all, the selection of cleaning tools should be careful: soft microfiber cloths, sponges, or special glass cleaning brushes should be used, and hard tools such as steel wool and hard bristle brushes should be avoided. These tools will scratch the surface of glass and increase the risk of mildew.
Secondly, the selection of cleaning agents is particular. Ordinary dust can be wiped directly with clean water; if there are stains such as oil and fingerprints on the surface of glass, it is recommended to use a neutral glass cleaner (with a pH value between 6 - 8), and avoid using washing powder, soap with strong alkalinity, or toilet cleaners with strong acidity. When using a cleaning agent, it should be diluted first, then applied to the surface of glass, left to stand for 1 - 2 minutes, wiped with a wet cloth, and finally dried with a dry cloth - the residual water is the "hotbed" of mildew and must be completely removed, especially the parts such as the edges and gaps of glass that are prone to water accumulation.
For glass with slight "mold spots" (hazy surface, white spots), you can try to clean it with a white vinegar solution (mixed with white vinegar and water in a ratio of 1:10) or a special glass mildew remover: spray the solution on the mold spots, let it stand for 5 minutes, then wipe repeatedly with a soft cloth until the mold spots disappear, and finally rinse with clean water and dry. However, it should be noted that if the mold spots have penetrated into the interior of glass (such as the appearance of mesh - like lines and darkening color), it indicates that the silicate skeleton on the surface of glass has been seriously corroded. At this time, cleaning can only remove the surface stains and cannot restore the transparency of glass. If such glass is used in scenarios with high transparency requirements such as doors, windows, and lenses, it is recommended to replace it in time.
(3) Special Scenarios: Targeted Protection to Extend the Service Life of Glass
Glass in different scenarios faces different "mildew risks" and requires targeted protection:
3. Common Misunderstandings: These "Maintenance Methods" Are Actually Damaging the Glass
In the daily maintenance of glass, many people will fall into some misunderstandings. It seems that they are "cleaning and maintaining", but in fact, they are accelerating the damage and mildew of glass, which needs special attention:
Misunderstanding 1: Using alcohol or white vinegar to clean glass directly. Although alcohol and white vinegar have a certain cleaning effect, alcohol has strong volatility, which will accelerate the evaporation of water on the glass surface, cause the glass surface to dry and generate static electricity, and make it easier to absorb dust; white vinegar is an acidic substance, and long - term direct use will corrode the silicate skeleton on the glass surface. Especially for special glass such as coated glass and Low - E glass, it will damage the coating on the surface and reduce the performance of glass. The correct way is to use alcohol or white vinegar after dilution (mix alcohol and water in a ratio of 1:10, and white vinegar and water in a ratio of 1:10), and it should not be used frequently.
Misunderstanding 2: Scratches on the glass surface do not affect use and do not need to be handled. Scratches on the glass surface not only affect the appearance but also become the "entrance" for water molecules and pollutants, accelerating mildew. If the scratch is shallow, a special glass polishing agent can be used for repair; if the scratch is deep, it is recommended to replace the glass in time to avoid the scratch expanding and causing the glass to break or mold.
Misunderstanding 3: Using hot water to wash glass after it gets moldy. Hot water will increase the activity of water molecules, accelerate the hydrolysis reaction, and instead make the mold spots more difficult to remove, and even aggravate the corrosion of glass. The correct way is to clean it with room temperature water or warm water, combined with a neutral cleaner or mildew remover.
Misunderstanding 4: Not cleaning glass for a long time, thinking that "the cleaner it is, the easier it is to get dirty". This idea is completely wrong. Pollutants such as dust and oil on the glass surface will react with moisture and carbon dioxide in the air to form corrosive substances. Long - term non - cleaning will cause pollutants to penetrate into the interior of glass and cause serious mildew. At that time, even if cleaned again, it is difficult to restore the transparency of glass.
4. Conclusion: Scientific Maintenance to Keep Glass Crystal Clear for a Long Time
As a material widely used in daily life and industry, the "mold" problem of glass is not unpreventable. As long as we understand the chemical principle of its mildew, start from the three core dimensions of "controlling the ambient temperature and humidity, cleaning pollutants in time, and avoiding physical damage", and cooperate with targeted scenario protection, we can effectively delay or even avoid the occurrence of glass mildew.
In daily maintenance, remember the principles of "dryness is the core, cleaning should be timely, tools should be gentle, and protection should be targeted", and avoid common maintenance misunderstandings. In this way, glass can always maintain a crystal - clear appearance and extend its service life. Whether it is glass doors and windows, utensils in the home, or glass plates and lenses in industry, scientific maintenance can not only improve the user experience but also reduce the replacement cost caused by mildew, achieving the goal of "long - term durability".
