4.2 Chemical Texture: Perms & Relaxers

4.2 Chemical Texture: Perms & Relaxers

Chemical texture services permanently change the shape of hair by altering its internal bonds. The Texas operator exam expects you to know which bonds each chemistry attacks, the pH ranges, the processing/neutralizing sequence, and the safety steps -- and to tell a perm apart from a relaxer chemically, not just by result.

The Bonds That Make Texture Possible

The cortex holds three side bonds. Hydrogen bonds and salt bonds are physical (temporary) and broken by water or pH change -- they govern wet sets and blowouts. The disulfide bond (also called the cystine or sulfur bond) is a strong chemical bond, and it is the only one that permanent waving and chemical relaxing target. Break and reform disulfide bonds and the new shape is permanent.

Permanent Waving Chemistry

A cold wave perm uses ammonium thioglycolate ("thio"), an alkaline reducing agent at about pH 9.0-9.6. The waving (reducing) lotion adds hydrogen to break disulfide bonds, softening the hair so it conforms to the rod. After processing you rinse, blot, and apply the neutralizer, an oxidizing agent (usually hydrogen peroxide or sodium bromate) that removes the added hydrogen, reforms the disulfide bonds, and rehardens the hair in its new curled shape. Skipping or shortcutting the neutralizer leaves bonds broken and curl will not hold.

True acid-balanced waves use glyceryl monothioglycolate (GMTG) at a lower pH (~7.0-8.2) and usually require outside heat (a dryer) to process; they are gentler on fragile, porous, or tinted hair than alkaline thio. Exothermic waves create their own heat through an oxidation reaction when an additive is mixed in, while endothermic waves require an outside heat source. Knowing which lotion the service uses tells you whether to apply heat and how aggressively the hair will process.

Hair condition drives lotion choice. Porous or damaged hair processes faster and is better matched to a milder acid-balanced wave, while resistant hair with a tight, compact cuticle needs the higher pH of an alkaline thio lotion to soften. Always analyze porosity, elasticity, and texture before selecting product strength.

Wrapping and Processing

Rod size determines curl size: small rods make tight curls; large rods make loose waves. The base section should be no larger than the diameter of the rod so the hair sits cleanly on its base. Wrapping methods include the croquignole technique (hair wound from the ends toward the scalp, common in standard perms) and the spiral technique (wound along the length of the rod for long, elongated curls). End papers (porosity papers) control the ends and prevent fishhooks -- bent, frizzy ends caused by folded hair.

Before wrapping, perform a preliminary test curl wraps and a finger test during processing. Take a test (preliminary) curl -- unwind a rod partway and check for a firm, well-defined S-shaped wave that matches the rod size -- to judge when the hair is fully processed. Overprocessing breaks too many bonds and leaves hair frizzy, weak, or straight at the ends; underprocessing leaves a limp, loose curl that will relax quickly. Processing time, not just lotion strength, controls the result, so the test curl is the deciding step.

Relaxer Chemistry

Relaxers straighten by breaking disulfide bonds. There are two distinct chemistries, and the exam tests the contrast:

• Hydroxide (lye) relaxers use sodium hydroxide (NaOH) at a very high pH of about 12-14. They straighten by lanthionization, which permanently removes a sulfur atom and converts the cystine bond into a single lanthionine bond. This change is not reversible and cannot be neutralized back -- you stop it only by rinsing and using a neutralizing (acid-balanced, anti-alkali) shampoo.
• No-lye / no-mix relaxers use guanidine, calcium, lithium, or potassium hydroxide at roughly pH 9-11, milder on the scalp but they can leave calcium buildup that dries the hair.
• Thio relaxers use ammonium thioglycolate (pH ~10) -- the same family as perms -- and are reversible-chemistry products that must be neutralized by oxidation, unlike hydroxide.

Critical compatibility rule: thio and hydroxide chemistries are not interchangeable. Applying a hydroxide relaxer over thio-relaxed or thio-permed hair (or vice versa without proper conversion) causes severe breakage. Always know the client's prior chemical history.

Safety, Basing, and Strand Tests

Because hydroxide relaxers are caustic (pH up to 14), base the scalp with protective petroleum cream. Base relaxers require basing the entire scalp before application; "no-base" relaxers contain a built-in protectant in the cream, but you still apply base around the hairline, the ears, and the neckline to prevent burns. Wear gloves, and never shampoo, scratch, or brush the scalp before a relaxer service -- any abrasion lets the chemical burn the skin.

Apply relaxer to new growth only on a retouch and keep it off previously relaxed hair to prevent overlapping, the leading cause of breakage at the line of demarcation. Smooth from the most resistant area first and work quickly within the manufacturer's timing. Always perform a strand test to confirm the hair can withstand the service and to gauge timing. After processing, rinse thoroughly, then shampoo with a neutralizing (acid-balanced, anti-alkali) shampoo that lowers pH and stops the action; condition to restore the acid mantle.

Key safety summary:

• Base the scalp and hairline before any hydroxide relaxer.
• Do not shampoo or irritate the scalp beforehand.
• Apply to new growth only on retouches.
• Wear gloves and rinse with cool-to-tepid water.
• Follow the strand test result for timing.

Common exam traps: confusing neutralizing by oxidation (the peroxide/bromate step for thio) with the neutralizing shampoo step (for hydroxide), assuming a relaxer can be "reversed" (lanthionization is permanent), and mixing thio and hydroxide chemistries on the same hair, which causes severe breakage.